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Atopy refers to a genetic predisposition to developing allergic diseases, while atopic march is the natural progression and evolution of these allergic diseases. Atopy is commonly due to an exaggerated immune response towards allergens in the air or food. Allergic diseases such as atopic dermatitis, allergic asthma and allergic rhinitis affect 1 in 4 people globally, and the incidence of allergy continues to rise over the years.

Allergy diseases are fascinating in the sense that one tends to develop the diseases chronologically from childhood atopic dermatitis and food allergy to eventual progression of asthma and allergic rhinitis. This intriguing allergy progression phenomenon is time-based, involves the evolution and involvement of the skin-gut-respiratory system and is termed the Atopic March.

In this article, we highlight the manifestations in atopic march, the current clinical hypothesis behind these allergic diseases and discuss certain medical strategies to prevent or halt the progression of atopic march.

The Chronological Progress of Atopic March

The initial manifestation of atopic march involves atopic dermatitis, also known as eczema. The atopic march classically continues with food allergy, and eventually ends with progression to allergic asthma and allergic rhinitis. Children with atopic dermatitis have a 6 times higher chance of developing food allergies. 60% of children with atopic dermatitis may eventually develop asthma/ rhinitis later in their childhood. 

Eczema, or atopic dermatitis, is a chronic skin condition causing itchy, inflamed, and dry patches that flare up due to irritants, allergens, or genetics.

Atopic dermatitis

Atopic dermatitis is a recurring and relapsing inflammatory skin disorder whereby one presents with dry skin, inflamed, and itchy skin. Atopic dermatitis tends to occur in early life. It affects about 30% of children and can manifest its symptoms as early as less than 6 months of age. Atopic dermatitis is due to a complex combination of genetic and environmental factors. It is postulated that due to the impaired skin barrier in atopic dermatitis, external allergens are able to interact with the internal skin and immune cells leading to sensitisation of the immune system and manifestation of allergic response.

Food allergy

Food allergy frequently occurs simultaneously with atopic dermatitis during early childhood and is an indicator and risk of a person to be likely to progress with subsequent atopic march. Children and infants with food allergy develop allergic asthma earlier than those without food allergy. Those patients with food allergy can have an exaggerated and hypersensitivity and inflammation of the airway. 

Allergic rhinitis and Allergic asthma

Allergic rhinitis and allergic asthma are two allergic respiratory conditions that are closely linked. Environmental factors such as dust mite particles, air pollution, pollen, pet dander, food proteins/allergens can play a role in the development of allergic rhinitis and allergic asthma.

In allergic rhinitis, there is chronic recurring inflammation of the mucosal layer of the upper respiratory tract with predominant involvement of the nose passage leading to recurring bouts of sneezing, watery and blocked nose, itchy eyes, etc. Recurring allergic rhinitis can also stimulate and trigger contraction of the lower respiratory system such as the lungs muscles and tissues eventually lead to chronic inflammation, spasm and hypersensitivity of the lungs — allergic asthma.

Possible Causes of Atopic March

There remain gaps in the understanding of the progression of atopic march. A few theories have been hypothesised to explain the phenomenon.

Atopic march is the progression of allergic diseases from infancy to childhood, typically starting with eczema, followed by food allergies, asthma, and allergic rhinitis.

Impaired skin barrier

The skin functions as a physical layer to shield the body against external noxious agents. When the skin barrier is inflamed and impaired, it is ineffective in defending the body against environmental triggers such as pollutants, allergens, infections and other pathogens. The term transcutaneous sensitisation describes the allergenic proteins entering the body via leaky skin, leading to sensitisation of the immune system and development of atopic dermatitis — the first step of the atopic march and subsequent other allergic diseases.

Genetic disruption with filaggrin gene mutation

Filaggrin is a protein vital as part of the structure and component of the skin layer (stratum corneum). There is association of genetic mutation of filaggrin protein with those with atopic dermatitis. The integrity of the skin layer is compromised in those with filaggrin gene mutation, causing a weaker skin barrier and, hence, easier access of allergenic protein to the immune system, which can result in atopic diseases.

Interactions with environmental factors 

Airborne and food particles such as dust mites, fungi, pollen, insects, pet dander, peanuts, milk, seafood etc., can behave as allergen proteins. Upon exposure to the skin, gut, respiratory tract, they are able to trigger an exaggerated immune response leading to atopic symptoms. 

Interestingly, certain environmental proteins can also function as an adjuvant (facilitator) to other allergenic proteins to cause allergy.

Microbiome changes

The microbiome in the skin, intestine and the lungs interacts — this is known as ‘inter-organ cross-talk’, and is observed in atopic march. The skin microbiome in a person with atopic dermatitis differs from a person without atopy, with increase in Staphylococcus spp bacteria. It is also noted that the gut microbiome is less diversified in infants with atopic dermatitis and food allergy. The shift of the gut bacteria has been associated with allergic respiratory inflammation. Although the findings in the pattern of microbiome in the human body remain a novel concept, there is strong correlation between alteration of the body’s microbiome and atopic march. 

Can we stop atopic march with modern medicine?

Understanding of the natural progression of atopic march is imperative in managing the progression of atopic march. Although the current understanding of atopic march remains incomplete and there is no easy way to halt the progression of allergy, we can still utilise current clinical knowledge of the disease and manage the allergic progress.

Atopic dermatitis

Moisturiser and appropriate topical medication (commonly involving steroids) remain the key backbone in the management of atopic dermatitis. Aside from this ubiquitously known fact, we would like to share tips that are relevant, yet commonly neglected here:

Identifying those who are predisposed to a lifelong chronic atopic disease (atopic march) is paramount as the window period during early life should be targeted for treatment intervention. Maintaining a good skin barrier is essential. Appropriate skin care and management of atopic dermatitis can prevent further sensitisation of food or aero-allergens, subsequently reducing the risk of progression of atopic march.

Food allergy

Managing food allergy, avoiding repeated triggers is beneficial as those with atopic dermatitis and food allergy has shown to be more likely to continue the atopic march progression to the final respiratory allergic symptoms.

Asthma inhalers help with allergic asthma by relaxing airway muscles and reducing inflammation, making breathing easier and preventing flare-ups.

Allergic rhinitis and allergic asthma

While both allergic rhinitis and allergic asthma are considered the end point of atopic march, managing both conditions can improve a person’s quality of life tremendously. The ability to pinpoint the triggering allergens and receive targeted immunotherapy suggest there is a glimpse of hope in managing atopy symptoms.

Take home messages

References:

  1. Yang L, Fu J, Zhou Y. Research Progress in Atopic March. Front Immunol. 2020 Aug 27;11:1907.
  2. Nibbering B, Ubags NDJ. Microbial interactions in the atopic march. Clin Exp Immunol. 2020 Jan;199(1):12-23.
  3. Hill DA, Spergel JM. The atopic march: Critical evidence and clinical relevance. Ann Allergy Asthma Immunol. 2018 Feb;120(2):131-137.
  4. Bantz SK, Zhu Z, Zheng T. The Atopic March: Progression from Atopic Dermatitis to Allergic Rhinitis and Asthma. J Clin Cell Immunol. 2014 Apr;5(2):202.

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Hormones can affect immune responses in the body, potentially intensifying our allergic reactions.

Hormones are chemicals that are produced by the endocrine system of the body to maintain the body’s equilibrium known as homeostasis. Hormone levels can fluctuate either physiologically (natural biologically) or due to external factors, such as infection, environmental factors, drugs etc. Interestingly, our hormone levels can affect allergies or predispose a person to allergic symptoms.

In this article, we explore the effects of common hormones, such as sex hormones, thyroid hormones, stress hormones and insulin on common allergies like eczema, allergic rhinitis and asthma.

Sex Hormones

Sex hormones fluctuate physiologically throughout our reproductive age of life. We may notice our allergy symptoms becoming more prominent or worsen during certain times of our life. Here, we discuss the role of common sex hormones, such as oestrogen, progesterone and testosterone, in affecting a person’s allergy symptoms.

In asthma, oestrogen can bind with oestrogen-receptors on the lung tissues, stimulating inflammation and activation of immune cells in the lungs. Oestrogen regulates chemical protein (chemokine) production, causing mast cells (a type of allergy cell) to degranulate (breakdown), leading to airway cells and airway muscles to be inflamed and becoming overreacting towards allergens. Progesterone hormone prevents mucus clearance from the airway.

In atopic dermatitis (eczema), one is more susceptible to the sex hormones in comparison to those without atopic dermatitis. Oestrogen generally has a positive effect on the skin barrier, reducing the risk of eczema flare ups. Contrarily, both progesterone and testosterone can be detrimental in maintaining a good physical skin barrier, leading to more predisposition of flare up of skin condition under the influence of both hormones. 

In allergic rhinitis, the nose tissues and secretory glands can interact with sex hormones, such as estrogen. This, in turn, leads to blood vessels growth, tissue swelling, inflammation and an increased response to allergies and mast cells degranulation. This cascade of activities within the body result in the clinical manifestation of upper respiratory allergy symptoms of rhinitis. 

Allergic AsthmaAtopic DermatitisAllergic Rhinitis
Effects of Sex Hormones on allergiesDue to the influence of oestrogen and progesterone, asthma can be exacerbated during peri-menstrual period, pregnancy phase and the exacerbation decline after menopause.
Testosterone has an anti-inflammatory effect in asthma conditions.
Due to physiological fluctuation of sex hormone levels during the menstrual cycle, one may notice exacerbation of skin condition just before period or during pregnancy.Symptoms of allergic rhinitis can be worsened during ovulatory period or during pregnancy period.

Stress Hormones

Cortisol, our body’s stress hormone, is produced by a pair of adrenal glands that reside on the tip of both kidneys. The stress hormone is controlled by the brain — hypothalamus and the pituitary. 

Stress can result in worsening of allergic symptoms. Generally, stress causes general inflammation of the body. In asthma, stress is responsible for causing lung inflammation and dysregulation of the immune system, leading to susceptibility to allergens and asthma exacerbation. Interestingly, mood disorders such as depression, anxiety and attention deficit hyperactivity disorders are associated with worsening of allergic rhinitis or atopic dermatitis symptoms — hence termed ‘allergic mood’. 

Due to the physiological day-night fluctuation of stress/ neuro-hormones, one with atopic dermatitis may notice worsening itch at night.

The thyroid gland modulates metabolism, energy and growth by producing hormones.

Thyroid Hormones

The thyroid gland is a symmetrical, butterfly-shaped gland situated in front of a person’s neck. The thyroid gland produces thyroid hormones that play essential roles in a person’s overall metabolism. The thyroid levels can fluctuate due to physiological causes, stress, infection, and even autoimmune or brain/pituitary disorders. When the thyroid levels are too high, it is termed “hyperthyroidism”. Conversely, “hypothyroidism” is used to describe thyroid levels that are too low.

Imbalance of the thyroid hormones can exacerbate asthma symptoms. An overproduction of thyroid hormones can cause inflammation, leading to high levels of immune cells and asthma exacerbation. In hypothyroidism, due to slower overall metabolism, there is reduced oxygen usage in the lungs, and slower lung tissue/muscle clearance of air/allergens leading to predisposition of asthma symptoms. Managing thyroid levels back to normal levels can alleviate and aid the overall management of asthma treatment.

Low thyroid level is associated with allergic rhinitis due to reduced mucous/nose tissue clearance of infection/ allergy particles, increased predisposition to various sinus infections and allergies.

While thyroid disorders do not have a direct relationship with atopic dermatitis, low thyroid levels can worsen existing dermatitis as hypothyroidism can cause itching and skin dryness.

Insulin and Diabetes Mellitus

Diabetes Mellitus is a chronic endocrine disorder due to dysregulation of the glucose in the body resulting from insufficient or ineffective insulin in the body to process the blood glucose. We discussed the relationship of type 2 diabetes mellitus and allergies.

Type 2 diabetes mellitus is the result of ineffective insulin to break down blood glucose due to insulin resistance over time. Frequently, type 2 diabetes mellitus can be associated with other metabolic disorders such as obesity, which both conditions impair lung function leading to exacerbation of asthma. A good control of type 2 diabetes mellitus can improve a person’s overall asthma symptoms.

The relationship between type 2 diabetes and atopic dermatitis/allergic rhinitis remains much to be elucidated, and clinical literature remains contradictory.

Understanding our hormones can help us manage our allergies

While the association between hormones in our body and allergic symptoms remains an area not commonly discussed, understanding the link between them can potentially ameliorate and manage allergies more effectively resulting in better quality of life. 

Importantly, learning the association between hormone fluctuations and allergy symptoms allow both patient and physician to strive towards a more personalised, holistic health management plan to control allergies. 

References:

  1. Weare-Regales N, Chiarella SE, Cardet JC, Prakash YS, Lockey RF. Hormonal Effects on Asthma, Rhinitis, and Eczema. J Allergy Clin Immunol Pract. 2022 Aug;10(8):2066-2073.
  2. Kanda N, Hoashi T, Saeki H. The Roles of Sex Hormones in the Course of Atopic Dermatitis. Int J Mol Sci. 2019 Sep 20;20(19):4660.
  3. Cardet JC, Ash S, Kusa T, Camargo CA, Jr., Israel E. Insulin resistance modifies the association between obesity and current asthma in adults. Eur Respir J 2016; 48:403–10.
  4. Wei J, Gerlich J, Genuneit J, Nowak D, Vogelberg C, von Mutius E, et al. Hormonal factors and incident asthma and allergic rhinitis during puberty in girls. Ann Allergy Asthma Immunol 2015; 115:21–7 e2.
  5. Danesh MJ, Murase JE. A review of the clinical and immunologic effects of estrogen on atopic dermatitis. Obstet Gynecol Int J. 2015;2(3):100-103.
  6. Sun Q, Li J, Gao F. New insights into insulin: The anti-inflammatory effect and its clinical relevance. World J Diabetes 2014; 5:89–96.
  7. Philpott CM, El-Alami M, Murty GE. The effect of the steroid sex hormones on the nasal airway during the normal menstrual cycle. Clin Otolaryngol Allied Sci 2004; 29:138–42

Itching is generally an irritating sensation that results in scratching the affected site. Commonly, itch is associated with infection, allergy, insect bites, or underlying psychiatric conditions, such as anxiety.  

Mucosal itches, on the other hand, refer to itch or irritation that occur in the mucosal linings of the body. Simply put, mucosal areas are the connecting junctions between the external skin and the internal body, such as the vagina, anus, mouth, nose, eyes and ears. We tend to neglect the mucosal areas, yet they play a pivotal role in safeguarding our body against external particles, proteins and even harmful pathogens. 

The understanding of itching over mucosal surfaces is less discussed. We want to increase the awareness about mucosal itching, the possible causes of mucosal itching at different locations, highlight the common causes and encourage appropriate treatment to the respective conditions.

Why does a person experience itch?

Itch is often triggered by a stimulus. The stimulus is picked up by sensory receptors over the affected site. These sensory receptors (known as nociceptors) then activate sensory nerve fibres, which are also known as unmyelinated C-fibres. The nerve fibres will transport the stimulus impulse to the spinal cord and the brain, triggering the perception of ‘itch’ and resulting in a cascade of motor reflexes involving scratching the itch site. Interestingly, both pain and itch share the same sensory fibres, and both symptoms can occur concurrently.

Itch over the Oral Mucosa

The oral mucosa covers the inner cheek (buccal area of the mouth), lips, gums, teeth, the roof of the mouth (known as the palate), the floor of the mouth, tongue and back of the throat. These mucosal regions are highly covered with nerve endings. The maxillary and mandibular nerve from the trigeminal branch supply most regions of the oral mucosa. The back of the oral cavity is also innervated by the vagus nerve.

Common causes of itch over the oral mucosa

Provocation of external allergens in the form of airborne or food particles can trigger the sensory nerve endings in the oral mucosa and result in the unpleasant sensation of itch. Often there can be associated nasal hypersecretion symptoms, watery itchy eyes as well

Oral allergy syndrome aka pollen-food allergy syndrome/ latex-fruit allergy syndrome/ dustmites-crustacean allergy

What can I do?

Itch over the Nose, Eye and Ear Mucosa

The nose sensation is supplied by the trigeminal nerve. The ophthalmic nerve supplies the mucous membrane over the eyes, nasal sinuses. The ear mucosal areas are supplied by both the trigeminal nerve and vagus nerve. Similar nerve branches also innervate the oral cavity as discussed previously. This rich network of nerves pick up itch stimuli sending impulses to the spinal cord and brain, resulting in itchy sensation.

Common causes of itch over the nose, eyes and ear mucosa

  1. Allergic rhinitis (Rhinoconjunctivitis)

Similarly, an allergic exposure to the eyes or ears can trigger nasal or even oral symptoms, suggesting the interlinking nervous network of these mucosal areas.

What can I do?

Itch over Vaginal Mucosa

The mucosal region of the vagina is meant to protect the body from external pathogens and facilitate sexual functions. Itch is a sensation meant to be a warning sign to a person that there is an irritation, inflammation or infection brewing. The clitoris, the pubis, vulva, even the cervix has nerve fibers that can stimulate itch sensation. Change in the surrounding temperature, pH, tissue damage, infections can potentially trigger itch nerve signaling and inflammatory response.

Common causes of itch over vaginal mucosa

Vaginal infection such as yeast (candida) infection can present with vaginal itch. Bacterial STDs such as chlamydia trachomatis, neisseria gonorrhea, trichomonas, mycoplasma genetalium, ureaplasma spp can contribute to vaginal itch.

Hormonal fluctuation, especially lacking in estrogen after menopause can result in itch due to poorer skin and mucosal barrier, and reduced glandular secretion. One may be more predisposed to itch sensation. 

Less commonly, yet important not to be missed, itching or pain over the vulva or vaginal area can be due to underlying cancer.

What can I do?

Itch over anal mucosa, often called pruritus ani, can result from irritation, infections, or conditions like haemorrhoids, requiring proper hygiene and treatment.

Itch over Anal Mucosa

The pudendal nerve is the sensory nerve group found over the sacrum/genital region for both male and female that plays an important role in receiving itch stimuli and result in motor reflex of recurring scratching. Itching over the anal mucosal region is more common in male and it affects 5% of the population.

Common causes of itch over anal mucosa

What can I do?

Take home message

Mucosal sites are the ‘guardian’ sites that connect the external skin with the internal body. In view of the nature of the mucosal sites, they are covered with large amounts of complex sensory nerves to pick up any potential threat in the form of inflammation, infection or allergy. 

Itch over the mucosal surfaces behave like alarm bells of the body, signaling potential external danger. Understanding different mucosal itches at different sites and the possible causes aid correct diagnosis and ensure appropriate treatment to be given.

References:

  1. Potenzieri C, Undem BJ. Basic mechanisms of itch. Clin Exp Allergy. (2012) 42:8–19. 
  2. Kim M, Ahn Y, Yoo Y, Kim DK, Yang HJ, Park HS, et al. Clinical manifestations and risk factors of anaphylaxis in pollen-food allergy syndrome. Yonsei Med J. (2019) 60:960–8. 
  3. Muluk NB, Cingi C. Oral allergy syndrome. Am J Rhinol Allergy. (2018) 32:27–30. 
  4. Wagner S, Breiteneder H. The latex-fruit syndrome. Biochem Soc Trans. (2002) 30:935–40. 
  5. Tuano KTS, Davis CM. Oral allergy syndrome in shrimp and house dust mite allergies. J Allergy Clin Immunol Prac. (2018) 6:2163–4. 
  6. Woelber L, Prieske K, Mendling W, Schmalfeldt B, Tietz HJ, Jaeger A. Vulvar pruritus-causes, diagnosis and therapeutic approach. Deutsches Arzteblatt Int. (2020) 116:126–33. 
  7. Siegler E, Segev Y, Mackuli L, Auslender R, Shiner M, Lavie O. Vulvar and vaginal cancer, vulvar intraepithelial neoplasia 3 and vaginal intraepithelial neoplasia 3: experience of a referral institute. Israel Med Assoc J. (2016) 18:4.
  8.  Siddiqi S, Vijay V, Ward M, Mahendran R, Warren S. Pruritus ani. Ann R Coll Surg Engl. (2008) 90:457–63. 
Obesity and allergies are closely interconnected through chronic inflammation and altered immune responses. 

In Singapore, obesity is defined as a body mass index (BMI) of more than 27.5. Obesity has a deleterious impact on a person’s health — with an increased risk of coronary heart disease, stroke, high blood pressure, diabetes, osteoarthritis, depression, poor sexual function, cancer, and more. 

The diet we consume is known to play a major role in the development of obesity. One that consists of mainly processed food and fast food which are high in calories and have minimal proper nutrients. Consuming this diet in the long run can lead to chronic surplus of calories intake, leading to weight gain. Currently, 38% of the people in the world is obese, and this trend is rising continuously.

In this article, we explore the association of obesity and common allergy medical conditions. This article is written in hope of highlighting the importance of managing weight to reduce risk of immunological conditions, hence improving one’s quality of life.

In obese individuals, adipocytes are enlarged, more metabolically active, and secret increased levels of pro-inflammatory cytokines. 

Physiological Inflammation from Obesity

In obesity, there is excessive build-up of fat tissues in the body — a condition known as adipogenesis. The fat cells known as adipocytes increase in size and numbers. The adipocytes produce chemicals and hormones known as adipokines that regulate the body’s overall wellbeing. In obesity, as there are more and bigger adipocytes, more adipokines are produced, leading to disruption of the body's internal equilibrium. 

Over time, with excessive adipogenesis, excessive adipocytes and adipokines production, the body is in constant oxidative stress and inflammation. It is postulated that this low grade inflammatory state of an obese person increases the susceptibility towards allergic conditions.

Obesity and Food Allergy

During the chronic inflammatory state of obesity, the gastrointestinal linings also undergo changes. The intestinal microbiome becomes less diverse, leading to a weaker intestinal barrier and increased permeability of food/ protein/ particles/ allergens through the intestine layer. The external proteins or allergens can pass through the intestinal linings into the blood circulation, leading to abnormal activation of the immune system and food allergies.

What can we do?

As obesity contributes to the development of food allergies;

Obesity can increase the risk and severity of allergic rhinitis.

Obesity and Allergic Rhinitis

Obesity is clinically shown to increase the risk of allergic rhinitis. However, this association is more seen in the paediatric group rather than in obese adults. Hormone and chemicals such as leptin and interleukin-1beta protein can be found in high levels in obese individuals. These proteins can activate the immune inflammatory response, increase susceptibility towards allergens and increase risk of allergic rhinitis.

It is also hypothesised that due to the pro-inflammatory state of obesity, the mucus membrane lining of the nose passage can be constantly swollen and inflamed, leading to increased permeability of the external allergenic particles which result in activation of the immune system and allergic symptoms in the form of rhinitis.

Interestingly, a person with allergic rhinitis has an increased risk of becoming obese due to hampering of physical activities following rhinitis symptoms or becoming sedentary due to side effects of medications (such as drowsy antihistamines) of rhinitis.

What can we do?

Due to the association discussed above between obesity and allergic rhinitis;

Obesity can worsen asthma by increasing airway inflammation and strain on the lungs.

Obesity and Asthma

The relationship between obesity and asthma is stronger among the paediatric group with greater risk of developing asthma, more exacerbation of asthma, and harder to manage the condition.

The negative impact of obesity on causing respiratory inflammatory conditions such as asthma is through complex mechanisms. Firstly, there is an innate genetic susceptibility of having asthma. This is further coupled with low grade chronic inflammatory state in obesity, leading to structural changes of the respiratory tract. To make things worse, obesity is also implicated in hormonal changes and less microbiome diversity, leading to predisposition to environmental triggers (pollution/ allergens) of developing asthma.

High sugar and fatty diet in obesity can also reduce the lung function. As excessive fat tissues accumulate around the chest and abdomen, the movement of the lungs and chest wall muscles can be restricted, leading to increased work of breathing. 

In a vicious cycle, the repeated use of corticosteroid in asthma or poorly controlled asthma can also cause weight gain. Restricted physical activities may be seen in asthma patients. Weight gain can occur over time with a sedentary lifestyle.

What can we do?

As obesity contributes to the asthma and related long-term comorbidities;

Obesity and atopic dermatitis (eczema)

Obesity can affect the skin in a few possible ways. We know obesity promotes inflammatory processes in the body and can affect the hormones and chemical substances of the body.

People with obesity may have an impaired skin epidermis barrier due to increased sweating and increased blood pressure. The skin microbiome can be less diverse in a person with obesity, with more colonisation of Corynebacterium spp. There is less lipid content on the skin surface in an obese person, leading to faster skin dehydration, and increased risk of developing atopic dermatitis. Interestingly, one can have increased risk of developing atopic dermatitis if the mother is obese before pregnancy.

What can we do?

Weight loss has a beneficial effect in overall treatment of atopic dermatitis, hence promoting a healthy lifestyle and weight loss can complement the treatment of atopic dermatitis. Additionally:

What Have I Learnt Today?

References:

  1. Morąg B, Kozubek P, Gomułka K. Obesity and Selected Allergic and Immunological Diseases-Etiopathogenesis, Course and Management. Nutrients. 2023 Aug 31;15(17):3813.
  2. Han YY, Forno E, Gogna M, Celedón JC. Obesity and rhinitis in a nationwide study of children and adults in the United States. J Allergy Clin Immunol. 2016 May;137(5):1460-5.
  3. Guo X., Cheng L., Yang S., Che H. Pro-inflammatory immunological effects of adipose tissue and risk of food allergy in obesity: Focus on immunological mechanisms. Allergol. Et Immunopathol. 2020;48:306–312.
  4. McAleer JP. Obesity and the microbiome in atopic dermatitis: Therapeutic implications for PPAR-γ agonists. Front Allergy. 2023 Mar 27;4:1167800.
  5. Zhang, S., Zhang, B., Liu, Y. et al. Adipokines in atopic dermatitis: the link between obesity and atopic dermatitis. Lipids Health Dis 23, 26 (2024).
  6. Peters U, Dixon AE, Forno E. Obesity and asthma. J Allergy Clin Immunol. 2018 Apr;141(4):1169-1179.

Cow’s milk allergy can occur in anyone, including adults. However, it is a condition that more commonly affects the paediatric population. Diagnosis for cow’s milk allergy can be difficult and can often be confused with cow’s milk/ lactose intolerance. 

In this article, we’ll highlight the differences and similarities between milk allergies and milk intolerance, the underlying causes of a cow’s milk allergy, common questions that one may encounter, and practical ways to deal with cow’s milk allergy.

Is milk allergy and milk/lactose intolerance the same thing?

A milk allergy can trigger an exaggerated immune response in the body, causing symptoms such as rashes or hives. 

No, a milk allergy and milk/lactose intolerance are different. 

Milk allergy is an immune response to milk proteins. The body mistakenly identifies these proteins as harmful, producing specific antibodies against it. Upon repeated exposure to these proteins, the immune system triggers an exaggerated antibody response, leading to a cascade of chemical immune reactions, which manifest as signs and symptoms of milk allergy.

A lactose intolerance occurs due to the lack of the enzyme lactase, which is needed to digest lactose — a sugar found in milk. A milk protein intolerance is a non-allergic sensitivity to milk proteins, such as casein or whey. 

How can I differentiate milk allergy from milk/lactose intolerance?

In milk/lactose intolerance, one develops unpleasant gastrointestinal symptoms when they are unable to digest lactose effectively due to reduced amount of lactase.

The poorly digested lactose in the gut is subsequently being fermented by gut bacteria causing uncomfortable irritable-bowel-syndrome-like symptoms such as:

Contrary to milk or lactose intolerance, an individual with a true milk allergy will not be able to tolerate any amount of milk, while in the case of lactose intolerance, one may still be able to tolerate a small amount of milk.

Types of milk allergy responses

Immediate IgE related

This type of allergy can occur very fast within seconds to minutes upon consumption of cow's milk. In IgE related allergy response, once the body is exposed to the 'allergen' protein, there will be an immediate trigger of a cascade of inflammatory allergic response and release of IgE antibodies, leading to an acute allergic reaction.

Delayed IgE related

This type of allergy tends to occur slower over a period of hours up to 3 days after consumption of cow’s milk. The immune response tends to develop progressively over time, and usually this is non-IgE related, immune response can often drag on with symptoms for days to even weeks. One commonly confused the symptoms of delayed response with milk/lactose intolerance.

What are the signs and symptoms of cow’s milk allergy?

Milk allergy symptoms can occur within the first few months of human life (within the first 6 months of life), though less commonly symptoms can occur in adulthood. There is a spectrum of severity of milk allergy symptoms, making nailing the diagnosis difficult.

Rapid reaction 

Within hours after consumption of milk. Symptoms include:

Delayed reaction

From hours to days after consumption of milk. Symptoms include:

Anaphylaxis

An immediate, dangerous fulminant allergic response within seconds to minutes after consumption of milk. Symptoms include:

What causes cow’s milk allergy?

Cow’s milk is a rich source of nutrients for the body, with over 20 beneficial proteins.

In milk allergy, the body's immune system reacts to protein that is found in the milk, particularly in 2 types of proteins — casein and whey.

Casein protein is the main emulsifier in milk and it makes up 80% of the protein in cow’s milk and 20-60% of proteins in human milk. Casein is also found in high quantities in cheese, and can be used as a food additive/ emulsifier to stabilise processed food. 

Whey protein is the left over from milk when it is coagulated during the formation of cheese. Whey protein makes up 20% of cow’s milk, and about 60% of human milk. Whey protein is made up of 2 major proteins known as alpha-lactalbumin, beta-lactoglobulin. 

Whey protein is commonly seen in yoghurt and protein supplement (in building muscle mass). Whey protein can also be used as a food thickener.

What type of food commonly has cow’s milk protein?

Foods containing milk protein should be carefully avoided by individuals with milk protein allergies to prevent allergic reactions.

Common foods with milk protein include:

Reading food labels is important to pick up any cow’s milk protein content. If you are eating out, beware of possible milk in the food content. 

Extra caution should be taken if eating out in coffee shops, pizza shops and ice cream places. If in doubt, it is worth highlighting any history of food allergy or food restrictions to the restaurant staff.

How can I diagnose cow’s milk allergy?

The skin prick test is a quick and reliable method to identify allergic sensitivities by introducing allergens into the skin.

A good history with a clear timeline of exposure to milk allergens and presentation of the allergic symptoms is suggestive of cow’s milk allergy. Nonetheless, in the practical world, this can be much more difficult as one may be exposed to other food substances or environmental allergens or symptoms can be confounded with underlying intolerance.

Allergy tests may not be foolproof either, but may facilitate the history of presenting complaints:

You are advised to discuss any concerning symptoms with your doctor so that they can provide guidance on which tests can be offered to you to evaluate your condition further.

What is the treatment for cow’s milk allergy?

As there are no antidotes for cow’s milk or food allergies, the treatment is by eliminating the culprit allergen — milk from the diet.  

In situations when one has inadvertently consumed milk, medication such as antihistamine and steroid can reduce or abort allergic symptoms. In severe allergic response or anaphylaxis, one will require adrenaline injection or medical emergency to reverse the allergy.

As cow’s milk allergy is commonly seen in children, it is imperative to ensure the child still receives a healthy balanced diet and is taking supplements to replace the common nutrients that are found in milk. 

Breastfeeding is encouraged especially if the infant has cow’s milk allergy. 

As cow’s milk protein can be passed from mother who consumed it to the child through breast feeding, the mother should avoid food that contains cow’s milk protein if the infant has cow’s milk allergy. 

Alternative options such as soy formula milk may not be useful as some children may also have soy protein allergy. Due to high protein allergy cross-reactivity, those with cow’s milk protein are usually not suitable to take goat’s milk as well.

Understanding and determining the allergic components in milk proteins can aid prudent food selections to avoid allergy.

What have I learnt today?

References:

  1. Edwards CW, Younus MA. Cow Milk Allergy. [Updated 2023 Jun 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK542243/
  2. Regula P, Agress A, Rosenstreich D, Rubinstein A, Ramesh M. Adult-onset IgE-mediated cow's milk allergy-a rare phenotype. J Allergy Clin Immunol Glob. 2023 Jul 8;2(4):100142.
  3. https://allergyasthmanetwork.org/food-allergies/milk-allergy/

Allergic rhinitis (AR) is a common inflammatory airway disorder triggered by airborne-related allergens. While this is not a life-threatening medical condition, it can be debilitationg — affecting a person’s quality of life; causing poor quality of sleep, suboptimal work performance and social interaction impairment.

In this article, we want to understand the background science and immunology of allergic rhinitis and make sense of the current treatments available, including the exciting option of immunotherapy.

What is allergic rhinitis?

Allergic rhinitis is a common condition, affecting up to 30% of adults and 40% of children worldwide, often triggered by pollen, dust mites, or pet dander.

Allergic rhinitis is an upper airway disease resultant from sensitisation of allergens and proteins in the air during breathing. The classical symptoms involve the upper respiratory airway such as sneezing, nasal itch, increase nasal secretion, blocked nose and etc. Common inhalant allergens that can trigger allergic rhinitis include house dust mite particles, mould, animal dander, grass, birch and pollen, cockroach particles and more.

Immune Response in Allergic Rhinitis

In allergic rhinitis, following exposure to allergens, the immune response undergoes 2 phases:

  1. Early phase

The inhaled allergen protein will be ‘carried’ and ‘presented’ by a type of specialised cells known as Antigen Presenting Cells (APCs) to the nearby lymph nodes. Lymph nodes are ‘checkpoints’ in our body that store immune cells. 

The allergen proteins then trigger a cascade of inflammatory response from the immune cells. Immune cells that are commonly involved in this phase include T cells, B cells, IgE antibodies, mast cells, ILK-4, IL-13, histamine, prostaglandins, leukotrienes, TNF-alpha and etc.

  1. Delayed phase

Following 4-6 hours of exposure to allergen protein, there will be further chemical inflammatory response involving cells such as monocytes, granulocytes, protein elastase and etc.

*Understanding the involvement of immune cells is imperative as this becomes the target area of modern medicine in allergic rhinitis. 

The surge of inflammatory response in the early and delayed phase can be translated to the clinical symptoms of allergic rhinitis such as acute sneezing, itching, runny and block nose. Symptoms tend to abate when the allergen is withdrawn or avoided. 

Over time, with recurring exposure and recurring inflammatory immune response, repeated wax and wane of condition, remodeling of the affected airway can occur. This explains the association of chronic allergic rhinitis with more complicating ENT conditions such as nasal polyps, nasal hyperplasia, eosinophilic sinusitis and more.

Association of Allergic Rhinitis, Asthma and Chronic Rhinosinusitis

Interestingly, allergic rhinitis can be associated with asthma and chronic rhinosinusitis. The actual cause of association remains not fully understood. However, in these conditions, when one is exposed to allergens, there are similar inflammatory immune response demonstrated. 

Statistics show 10-40% of people with allergic rhinitis have concurrent allergic asthma, while 60-80% of asthma people have concurrent allergic rhinitis. In chronic allergic rhinitis, when there is repeated and resolution of airway inflammation, remodeling of the airway anatomy can result in chronic rhinosinusitis or nasal polyps and other ENT conditions.

Modern Treatment of Allergic Rhinitis

The ideal treatment of allergic rhinitis is to eliminate the triggering allergen from the environment. This, unfortunately, even with strict lifestyle allergenic control is not achievable and not practical.

Current management of allergic rhinitis involved a holistic approach of combining modern medicine with lifestyle control of environmental allergen to alleviate the condition.

Despite current conventional treatment is beneficial in controlling symptoms of allergic rhinitis, one may find taking daily pills, nose sprays or nasal irrigation a challenge and burden to our daily living. 

In addition, the symptomatic medications may even be limited in efficacy in some patients. To address these concerns, immunotherapy can be considered as a potential therapeutic option.

Allergen Specific Immunotherapy

Not all patients with allergic rhinitis find conventional medical treatment useful. Allergen specific immunotherapy (AIT) may come in useful and serve as a safe alternative treatment. AIT is a desensitization treatment where the triggering allergen is repeatedly introduced to the affected person over time to modify the immune response, inducing desensitization and amelioration of allergic symptoms after exposed to allergen.

AIT is arguably to achieve immune tolerance against allergen in the affected person over time following repeated re-exposure. In immunology terminology, with repeated exposure to the allergen, the body is able to normalised its own immune and inflammatory cells, preventing them from being triggered by allergens. AIT also produces allergen-neutralising antibodies that prevent allergen from triggering allergic inflammatory response. In clinical setting, 

Here, we can observe the treatment of allergic rhinitis has shifted from conventionally controlling symptoms with symptomatic medication to management and re-education of the immune response to an allergen, hence transforming the immune system that is exaggeratingly overactive to 'normal' immune reaction towards allergen protein. 

It is worth to note that in order to consider AIT, it is mandatory to identify the specific culprit allergen that causes the symptoms. Thankfully, again with modern medicine and technology, many of the common allergens can be picked up with skin prick test or IgE RAST blood test.

Overall Effectiveness of Allergen Specific Immunotherapy

Medical literature over the years has shown consistently that AIT is useful in alleviating allergic rhinitis symptoms and standard medication burden. Currently, AIT can be considered in allergic rhinitis patients with specific IgE allergy that present with significant symptoms that affect their daily life, sleep despite conventional pharmacological treatment.

AIT demonstrates effective management of allergic rhinitis with concurrent allergic asthma. AIT has shown clinical significance in reduction of both allergic rhinitis and asthma symptoms, asthma exacerbations and hospitalisation. AIT also shows good clinical improvement in those with allergic rhinitis and concurrent rhinosinusitis disorders.

Furthermore, AIT when introduced during the early phase of allergic disease can prevent progression of allergic rhinitis to asthma or new allergen sensitisation. This is particularly useful and a beneficial option for the younger group people with allergic rhinitis. This can also serve as a backbone theory in further research and medical advancement into immuno-desensitisation related treatment.

What have I learnt today?

References:

  1. Sharma K, Akre S, Chakole S, Wanjari MB. Allergic rhinitis and treatment modalities: a review of literature. Cureus. (2022) 14(8):e28501. 
  2. Bousquet J, Anto JM, Bachert C, Baiardini I, Bosnic-Anticevich S, Walter Canonica G, et al. Allergic rhinitis. Nat Rev Dis Primers. (2020) 6:95. 
  3. Guerra S, Sherrill DL, Martinez FD, Barbee RA. Rhinitis as an independent risk factor for adult-onset asthma. J Allergy Clin Immunol. (2002) 109(3):419–25.
  4. Bousquet J, Schünemann HJ, Togias A, Bachert C, Erhola M, Hellings PW, et al. Next-generation allergic rhinitis and its impact on asthma (ARIA) guidelines for allergic rhinitis based on grading of recommendations assessment, development and evaluation (GRADE) and real-world evidence. J Allergy Clin Immunol. (2020) 145(1):70–80.e3. 
  5. Husna N, Tan SM, Md Shukri HT, Mohd Ashari NS, Wong KK. Allergic rhinitis: a clinical and pathophysiological overview. Front Med (Lausanne). (2022) 9:874114. 

Consuming seafood has become a popular food choice globally. However, there have been increasingly reports of adverse health reactions following consumption of seafood. A body’s adverse reaction towards shellfish can be allergic-related vs toxic-related.

Allergies to seafood or shellfish is one of the common food allergens that occur in both children and adult. Interestingly, one with shellfish allergies tend not to outgrow from childhood. Shellfish allergic symptoms tend to be more severe when compared to other food allergies. Shellfish allergy affects approximately 0.5-2.5% of populations, though the actual cases of shellfish allergies are likely under-reported or un-diagnosed.

While one can have true allergic reaction following consumption of shellfish, the body can also react badly as a result of toxins and infections from eating shellfish. Shellfish can also be contaminated by bacteria such as salmonella spp, vibrio cholera, listeria spp. These noxious bacteria when consumed into human body, have capabilities to release toxins to the bloodstream and trigger a cascade of inflammatory and infective response.

Understanding one’s clinical presentation and underlying the cause of adverse reaction to shellfish can be important in determining subsequent management and prevention of similar detrimental health symptoms.

What is defined as shellfish?

shellfish allergy singapore
The shellfish family is divided into two main categories: curstaceans and mollusks.

Although 'seafood' and 'shellfish' are both used loosely, interchangeably and ubiquitously, they may have different meaning. 'Seafood' is an umbrella term to include any 'edible particles found in the sea', while 'shellfish' includes those with 'shells' as part of their skeletal system. 

The shellfish family can be sub-categorised into crustaceans and mollusks. 

  1. Crustaceans include: 
  1. Mollusks can further be subdivided into

What are the symptoms of shellfish allergies?

Allergies occur when the body's immune system is exposed to a substance (known as allergen) that is generally harmless. The immune system overreacts and produces excessive inflammatory response leading to clinical manifestations of allergic symptoms.

The onset of shellfish allergic symptoms tends to be within seconds to minutes with involvement of the skin, airway and gastrointestinal system. There can be an array of clinical presentation:

In very severe cases, one can succumb to shellfish allergy due to development of life-threatening anaphylactic reaction. Anaphylaxis presents with generalised involvement of allergic symptoms with feeling of 'impending loom', fainting spells, tightening of airway, facial swelling, difficulty of breathing, wheezing and widespread body rashes. Immediate medical attention can reverse such situation, and delay of treatment can result in death.

One can also develop allergic symptoms following the inhalation or direct touching of the shellfish protein allergens. This can occur in fish handlers, or one who works in kitchen preparing shellfish meal, leading to sensitisation of the airway and the skin. In such cases, one can present with wheezing, asthma symptoms or itchy hives rashes upon close contact with shellfish. Hence, shellfish allergy can develop even without consuming shellfish. 

Why does a person develop shellfish allergy?

Tropomyosin is the main allergen found in shellfish that plays a vital role in shellfish allergies. Tropomyosin is a protein found in the muscle cells. It can be found in shellfish in both crustaceans and mollusks. 

One can have cross allergy reactivity between the shellfish family. For example, one may be allergic to crustaceans such as crab and also present allergic symptoms when consuming mollusks such as clam. Tropomyosin is stable to heat- hence one can still develop allergic symptoms after consuming shellfish that is boiled or cooked with heat. 

As tropomyosin allergen can also be found in dust mites, cockroach particles,  parasites and insects, there can be cross allergy reactivity between these substances. A person with shellfish allergy can have concurrent allergy towards dust mites, insects, parasites and etc, vice versa. 

Thankfully, those who has shellfish allergies usually do not have fish allergies as there is no cross reactive protein allergens between the two groups although both are aquatic edibles. The belief that shellfish allergy is due to iodine is untrue, hence one with shellfish allergies does not have increased risk of radiocontrast iodine allergy.

Other allergens that are found in shellfish include arginine kinase, myosin light chain kinase, and sarcoplastic calcium binding protein which can cause allergy reaction in the children group.

Shellfish allergy vs. Shellfish poisoning

While we tend to assume shellfish adverse reactions are due to an allergic response, one may have similar unpleasant symptoms due to shellfish poisoning. 

Shellfish poisoning or shock syndrome can present with symptoms mimicking an allergic reaction depending on the amount of shellfish and toxin concentration ingested. Symptoms, within minutes of consumption of poisonous shellfish, include: 

In more severe cases, neurological symptoms such as numbness and weakness of face, neck, arms and legs, or even paralysis up to 72 hours may occur. Shellfish poisoning can also be associated with headache, confusion and short-term memory loss.  

Occasionally, adverse symptoms associated with shellfish may not be the poison directly from shellfish. Shellfish can be contaminated with bacteria such as vibro spp, clostridium botulinum, staphylococcal spp, salmonella spp or even Norwalk virus that can present itself with acute gastrointestinal symptoms such as nausea, vomiting, diarrhea, or even fatality.

How is a shellfish allergy diagnosed?

If you have concern of shellfish allergies, you are encouraged to discuss your symptoms and concerns with your health care providers for further guidance on diagnosis and management of your symptoms.

How can we treat shellfish allergies?

Key learning points about shellfish allergies

References:

  1. Woo CK, Bahna SL. Not all shellfish "allergy" is allergy! Clin Transl Allergy. 2011 Jun 10;1(1):3.
  2. Lopata, A.L., Kleine-Tebbe, J. & Kamath, S.D. Allergens and molecular diagnostics of shellfish allergy. Allergo J Int. 2016; 25, 210–218. 
  3. Alonso LL, Armstrong L, Warrington SJ. Shellfish Allergy. [Updated 2022 Sep 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448089/

Allergies are exaggerated immune response towards allergens — substances that are usually not dangerous to the body. Allergy disease can be triggered by particles from the environment such as food, air pollutants, mould, mites, fur, medications, chemicals and etc.

As the worldwide populations are getting older, there are increasingly presentation of allergy conditions among the aged population. Allergy in the elderly is starting to emerge as a health issue. With rising age, ageing physiological changes will inevitably occur, with increase chances of developing chronic conditions including allergies. 

Occurrence of allergy in elderly can be due to immunosenescence — a process of physiological ageing of the immune system. This can be seen with progressive modification and ageing of the body tissue structure and immune system. The process of immunosenescence can also be further accelerated with concurrent medical conditions, drugs, and environmental factors.

Although allergy conditions are becomingly common in the elderly, it is a topic less discussed and thought of. This article is written in hope to increase awareness of allergy conditions in elderly, highlighting the possible clinical presentations and encourages readers to seek medical advice and treatment if there is a concern of chronic symptoms associated with allergy.

Immunosenescence

As we progress with time and age, the body undergoes constant changes. Our cells, tissues, organs and body system’s physical structure and function deteriorate as we grow old. The gradual physiological dwindling of human can result in increased susceptibilities towards 

infections, cancer, inflammation and allergy response. 

In addition, micronutrients such as vitamin D, zinc, iron which are imperative in maintaining the immune system, tends to be inadequate in the older age group. These further result in a deleterious impact in the elderly’s health, potentially present itself as allergies or immune-related diseases.

1. Ageing changes in the gut

As time goes by, the intestines have weaker general immune response, a higher permeability to particles and allergens and a slower gastric digestive ability. These physiological progress can further be altered by various medications that one may be taking due to other elderly chronic conditions. Poorer and ineffective digestion, persistent allergen proteins in the intestine, impaired intestinal barrier and increase permeability of the allergens can lead to abnormal immune response and allergies.

Allergy presentation of the gut

As we grow older, the structure and physiological changes of the alimentary system increases risk of food allergy in the elderly. Food allergy is often under-reported and under-diagnosed in the elderly. Clinical symptoms of food allergy in the older population can be slightly different from the younger or paediatric group. One can present symptoms later (rather than immediate) following consuming food substances that they are allergic to. 

There can be a wide range of symptoms severity. One can have:

to more severe symptoms such as:

Occasionally, systemic symptoms such as skin itch, hives, rhinitis, sneezing, wheezing or asthma can be associated with food allergies.

Common food particles that can trigger allergic response in elderly include seafood or shellfish, nuts, fruits, vegetables, alcohol and etc. 

2. Ageing changes in the respiratory system

The upper respiratory system and lower respiratory system of our body undergoing physiological ageing process. The internal linings of our nose, sinuses, upper airway tracts are covered with small nose mucosal cells known as the mucocilliary cells. These cells secrete mucous and trap external proteins and particles, allergens, pathogens and transfer them towards the throat/gullet and eventually cleared by our digestive system. As we grow older, these mucocilliary cells become less effective, leading to accumulation of mucus secretions, and reduce ability of the respiratory system to fight against infections and inflammation. Due to further repeated damaging of the mucosal cells from repeated respiratory infections over the years, the function of these mucocilliary cells even further deteriorate with time.

In the lungs, with age, the lung cells progressively loss its lung function resultant in less elastic lung tissues, weaker lung muscles, impaired airway barrier, less effective gas exchange in the lungs, increase in overall work of breathing and increase susceptibility to sensitisation of environmental allergens.

Allergy presentation of respiratory system
Exposure to environmental factors such as allergens, infections, pollution, can cause chronic inflammation of the airway tissues and mucosal cells. As time goes by, one can be sensitised towards allergens and present with recurring and intermittent rhinitis symptoms, such as:

Rhinitis in the elderly is commonly not addressed as it is not considered a life-threatening disease and there may be other concurrent health issues that is considered more ‘pressing’ or ‘important’. However, rhinitis can affect a quality of life — consequently in taking time off from work, polypharmacy and increase overall health care costs.

Asthma is a chronic inflammatory disease of the airway that can be genetically predisposed and can be further exacerbated and triggered by environmental caused such as allergies. Although asthma is a condition that tends to occur since young, late onset asthma can occur in older age groups. Persistent lower respiratory symptoms such as cough, wheezing, chest tightness, difficulty in breathing should warrant one to consider diagnosis of asthma and possible underlying allergies.

Common airborne allergens include dust mites, cockroach, pollen and grass, mould, animal dander and etc. Understanding possible allergies that contribute to chronic respiratory diseases can be beneficial to the elderly in symptoms and disease control.

skin allergies in elderly singapore
Understanding triggers and effective management for allergies can lead to healthier, more comfortable ageing.

3. Ageing changes in the skin

As the skin ages, both the skin layers of epidermis and dermis get thinner. There will be slower skin turnover, loss of collagen and normal skin structure, resulting in impaired skin barrier. The aged skin gets dehydrated easier, increase permeability to environmental stressors, particles and allergens. Over time, the skin has less ability to respond to external stressors due to poorer skin integrity. 

Allergy presentation of the skin

Itching is one of the most common sign and symptom that elderly patients can present in clinic. This can be associated with symptoms such as rash, blistering, pain and etc. These symptoms may seem mild and ‘unimportant’, though they can be presentation of an underlying skin allergy. The elderly are prone towards skin conditions such as eczema, contact dermatitis, hives (urticaria), drug allergies and etc.

What can one do if my loved ones are concerned of an allergy?

If you or your elderly family member have concerns of having an allergy, you are encouraged to speak your doctor on your symptoms. Sometimes, allergies may be able to be identified from history of exposure. However, in those that the allergies are not ascertained from the history, your doctor may offer you allergy tests to evaluate the allergies further.

Allergy tests such as skin prick tests or blood RAST test may be useful in further understanding a person’s allergies.

Is there treatment for elderly allergies?

What have I learnt today?

References:

  1. De Martinis M, Sirufo MM, Ginaldi L. Allergy and Aging: An Old/New Emerging Health Issue. Aging Dis. 2017 Apr 1;8(2):162-175.
  2. Ridolo E, Rogkakou A, Ventura MT, Martignago I, Incorvaia C, Di Lorenzo G, Passalacqua G. How to fit allergen immunotherapy in the elderly. Clin Mol Allergy. 2017 Oct 6;15:17
  3. Di Lorenzo G, Melluso M, Rodolico A, Seidita A. Allergic Diseases in the Elderly. Transl Med UniSa. 2023 Dec 29;25(2):52-62.
Your skin microbiome consists of trillions of microorganisms, and some help protect against harmful pathogens and support overall skin health.

The skin is the largest organ of the human body. Beyond the naked eyes, the skin is the home to millions of bacteria, fungi and viruses that are beneficial to us. When the skin is covered and colonised by these microorganisms, they behave as a protective barrier against invasion of external insults and pathogens.  

When there is a disequilibrium of the microenvironment of these commensal microorganisms, the physical skin barrier can be disrupted, following more growth and invasion of pathogenic microorganisms. This can result in chronic inflammatory skin conditions or even more severe systemic medical conditions.

In this article, we discuss skin microbiomes and their associated with common skin conditions, making sense with current existing clinical treatment and exploring the potential role of understanding skin microbiomes in future treatment of skin diseases.

What are the microbes that I can find on my healthy normal skin?

Our skin is made up of two main layers: the epidermis (the external layer) and dermis (the inner layer). The epidermis is made up of keratinocytes that are crosslinked together to function as a physical barrier against the external world.

We can sub-classify the skin areas broadly into 3 areas: 

Common bacteria that can be seen in the oily area of a normal skin include propionibacterium acne spp. Fungi such as Malassezia spp and Candida spp can be found in oily regions of the skin as well. In moist areas, bacteria such as Staphylococcus spp and Corynebacterium spp can be seen. In dry areas of the skin, Staphylococcus spp can also commonly be seen.

Interestingly our skin microbiomes change from birth to puberty/adulthood. Newborns that are delivered through C-section tend to have skin microbiomes of normal skin while newborn that are delivered vaginally tend to have skin microbiomes that are also found in the vaginal lining. The prepubertal skin microbiomes have a greater population of Staphylococcus spp and Streptococcus spp.  The population of microbiomes shifts and remodels during pubertal period as the skin becomes oilier following hormonal stimulation of the sebaceous glands. With that, in pubertal and adult skin, there are more thriving Propionibacterium spp, Corynebacterium spp, Malassezia spp etc.

What factors change the normal skin microbiome?

The skin microenvironment is kept in equilibrium by multiple factors such as temperature and humidity, pH, UV exposure, sebaceous oil production, etc. The accessorial tissues around the skin such as the sweat glands, sebaceous glands and hair follicles ensures the microenvironment is being maintained.

Unfortunately, over time with the process of ageing, immunity changes, external insults such as strong contactant, allergies and etc, disruption of the skin microbiomes equilibrium can happen, with more ‘bad’ bacteria and less ‘good’ bacteria colonising the skin, resulting in various skin diseases.

The Association Between Skin Microbiomes and Chronic skin diseases — How do we translate this to current clinical practices?

Acne is a common skin condition caused by clogged pores, excess oil, bacteria, and inflammation, often appearing as pimples, blackheads, or cysts.

Acne

Acne vulgaris is the most common chronic skin inflammatory disease after atopic dermatitis in the world. Acne occurs when there is inflammation of the skin resulting from blockage and excessive sebum production on the skin follicles. While the actual mechanism remains much elucidated, it is documented that one with acne has more colonisation of bacteria Propionibacterium acne (also known as cutibacterium acne). It is believed that Propionibacterium acne plays a role in comedone formation and the inflammatory process in acne.

Decreasing the amount of Propionibacterium acne has been shown to be beneficial in many acne patients and the idea is used as a target mechanism in the treatment of acne. Treatment options such as benzoyl peroxide, azelaic acid, antibiotics such as doxycycline, clindamycin and erythromycin can reduce the colonisation and inflammation caused by Propionibacterium acne

Rosacea

Rosacea is a chronic adult skin condition presented with recurring facial flushing, redness, pimple-like bumps. While the actual cause of rosacea remains unknown, microbiome mite- Demodex folliculorum is implicated in rosacea. Studies have shown that skin biopsy samples of rosacea patients have a high load of Demodex on inflamed affected skin, suggesting the link of the mite and the skin condition. Permetrin cream or oral ivermectin are offered as part of management of rosacea to reduce the colonisation of demodex mites on rosacea skin.

Atopic dermatitis / Eczema

Atopic dermatitis- presenting with chronic relapsing itchy, dry, red rashes is the most common skin condition worldwide which has a major negative impact on a person’s quality of life. The condition can be associated with other atopic conditions such as allergic rhinitis and asthma. While there is genetic predisposition and family history in atopic dermatitis, the distribution of skin microbiomes in atopic dermatitis may have its effect on a person’s clinical outcome.

Staphylococcus aureus has been well documented as a colonizer in atopic dermatitis. There is a correlation between the amount of the bacteria and the severity of the disease. The higher the density of the colonization of Staphylococcus aureus, the graver the inflammation. There is disruption of the normal microbiome skin environment in atopic dermatitis due to excessive colonization of Staphylococcus aureus. This results in impairment of skin barrier and susceptibility to other infections. 

In order to reduce colonization of Staphylococcus aureus, antibiotics (in the form of oral or topical) and bleach baths are used to manage eczema. Such treatment regimens can synergize the treatment outcome with conventional treatment of emollient, topical anti-inflammatory and systemic oral medications. 

Seborrheic dermatitis

Seborrheic dermatitis is a skin relapsing inflammatory condition affecting areas that are rich in sebaceous glands such as the face, scalp and body. One may notice the common exacerbating triggers such as hot weather, increase humidity, emotional heighten- which may all increase further production of sebaceous oil.

Fungi such as Malassezia spp are found in oily skin surfaces, and play a role in inflammatory response in seborrheic dermatitis. Antifungal treatment is used in combination with anti-inflammatory medication to effectively manage seborrheic dermatitis.

Is there a role for probiotics or prebiotics for skin conditions?

Probiotics are live microorganisms that when being introduced into the body sufficiently, produce a positive health outcome to the person. Prebiotics on the other hand are non-digestible food substances that can encourage the person to produce selectively certain ‘good’ bacteria in the body. Over the past decades, both probiotics and prebiotics are being marketed for their potential benefits in a person’s health for a wide range of diseases including gut symptoms such as irritable bowel syndrome, diarrhoea, to even treating vaginal infections.

For the context of skin, there is medical literature looking into the role of probiotics and prebiotics in atopic dermatitis, focusing more on children rather than adults. Studies for the role of these potentially beneficial supplements are still lacking for other common skin conditions such as psoriasis, acne, rosacea, etc. 

At this stage, probiotics and prebiotics are not considered a medical intervention for skin conditions. As a consumer or patient, one should be prudent in considering probiotics and prebiotics to avoid spending unnecessarily for non-clinically proven treatment due to marketing gimmicks. 

What have I learnt today?

References:

  1. Byrd, A., Belkaid, Y. & Segre, J. The human skin microbiome. Nat Rev Microbiol 16, 143–155 (2018).
  2. Ellis SR, Nguyen M, Vaughn AR, Notay M, Burney WA, Sandhu S, Sivamani RK. The Skin and Gut Microbiome and Its Role in Common Dermatologic Conditions. Microorganisms. 2019 Nov 11;7(11):550.

What is chronic pruritus?

Pruritus is a medical term for ‘itch’. Itch is an uncomfortable sensation that provokes a person to scratch. When the itching lasts more than six weeks, it is termed chronic pruritus [1].

Although itching is not a life-threatening symptom, it can have a profound negative effect on a person’s social life. It can cause difficulty sleeping and an inability to concentrate on work/studies or daily routine. Chronic pruritus can cause emotional distress and is associated with mental health conditions such as anxiety and depression [2]. To make things worse, frequent scratching or rubbing of the affected skin area can lead to injury or impairment of skin tissues, resulting in infections and other health complications.

In this article, we explore these itchy symptoms and explain the possible underlying causes in simple layman's terms. The article strives to educate and empower patients to better understand these common symptoms and seek medical attention when symptoms persist.

Chronic pruritus may not be life-threatening but can have a negative impact on a person’s life.

How common is chronic pruritus?

Chronic pruritus is a common symptom that can affect anyone at any age or in any walk of life. Approximately 22% of people may experience chronic pruritus throughout their lifetime [3]. The condition is commonly seen in elderly people who are above the age of 65 [4]. In Singapore, nearly half of the elderly may experience chronic pruritus [5].

Ever wonder how a person can feel ‘itchy’ and the need to scratch?

Though the sensation of ‘itch’ is a nuisance, it functions as a body’s self-protective mechanism. It is supposed to warn us against harmful external agents and protect our bodies. The itch sensation is comparable to other skin sensations such as touch, pain, etc.

Itch occurs when the itch-sensing nerve endings known as ‘pruriceptors’ on the skin are stimulated by heat, chemical, mechanical causes, infection, or even inflammation. Once the pruriceptors are activated, the ‘nerve signals’ will be delivered via the C-fibres that are present on the skin to the spinal cord and the brain. When we scratch or rub the affected area, the pain and touch receptors on the skin can also be activated. The concurrent pain and touch sensation can interfere with the itch sensation, resulting in temporary relief. However, the skin can be irritated or injured via scratching, eventually leading to a never-ending vicious itch-scratch cycle [6].

The itch-scratch cycle is a process where itching prompts scratching, which then exacerbates the itch, leading to more scratching.

When should I consider seeing a doctor for my persistent pruritus?

You should consider seeing a doctor for further checkups and treatment if your itch:

What are some questions regarding chronic pruritus?

There are a few key questions that you may want to consider preparing yourself before seeing your doctor to evaluate chronic pruritus further; these are:

What are the causes of chronic pruritus?

Chronic pruritus is a medical condition that can be tricky for patients and physicians to diagnose and manage.

We can split the causes of a persistent itch into broad categories, such as:

Skin-related 4causes

Skin-unrelated causes

In a real-world circumstance, a person may have multiple factors that contribute to experiencing a persistent itch. Unfortunately, sometimes, it may be impossible to pinpoint a single cause of chronic pruritus.

Chronic pruritus may be due to skin-related or non-skin-related causes.

What are the possible complications from chronic pruritus?

Prolonged, unattended itch can lead to a vicious itch-scratch cycle. Out of itch desperation, one may even resort to repeated rubbing and washing to achieve temporary relief of the symptoms. Nonetheless, all these actions can lead to injury of the normal skin barrier, resulting in skin infection or even scarring of the affected area.

Chronic pruritus can be uncomfortable, affecting the quality of social life. It is known that a person with chronic pruritus is predisposed towards mental health disorders such as anxiety and depression.

Furthermore, chronic pruritus can be more than a skin-deep issue. It may suggest underlying medical conditions that, if left unattended, may result in potential long-term systemic complications.

What can I expect from my doctor for chronic pruritus?

It is useful to discuss your symptoms with your healthcare providers. Depending on individual circumstances, your doctor may offer tests such as the ones below to identify the possible trigger of your persistent itch symptoms.

Tests offered may include:

What is the treatment for chronic pruritus?

If there is an underlying condition that causes the recurring of itch, the underlying medical condition needs to be addressed.

Chronic pruritus can be relieved with:

You can discuss with your doctor to understand more about the management of chronic itch symptoms.

What have I learnt today?

References

  1. SingHealth. (n.d.). What is chronic pruritus? Singapore Health. Retrieved from https://www.singhealth.com.sg/news/singapore-health/what-is-chronic-pruritus
  2. Sokolova, A., Rist, L., & Biedermann, T. (2023). Chronic pruritus: A comprehensive review. Journal of the American Medical Directors Association, 23(2), 255-266. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9885286/
  3. Kaffenberger, B. H., & Kaffenberger, J. A. (2023). Chronic pruritus: Assessment, diagnosis, and management. JAMA, 330(3), 291-299. https://jamanetwork.com/journals/jama/article-abstract/2819296
  4. Kage, P., Ständer, S., et al. (2021). Pathogenesis of chronic pruritus: An overview. Journal of Clinical Medicine, 10(3), 345-356. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7795219/
  5. SingHealth Duke-NUS. (n.d.). First local study on elderly perception of chronic pruritus. Retrieved from https://www.singhealthdukenus.com.sg/news/research/first-local-study-conducted-found-how-elderly-perceived-chronic-pruritus-prolonged-itch-and-results-may-help-in-pruritus-management
  6. Lavery, M. J., et al. (2022). Itch management: Understanding the itch-scratch cycle and its impact on chronic pruritus. Journal of the European Academy of Dermatology and Venereology, 36(4), 601-610. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8896504/

Experiencing discomfort after sex? Is it truly an infection or an allergy from the condom used?

In this article, we delve into the medical part of condom allergy, the possible predisposition to other forms of allergies and alternative options to mitigate your concerns.

condom allergy singapore
Latex condom allergy may result in discomfort after sex.

What is a latex condom allergy?

In latex allergy, a person’s immune system recognises the protein in latex and mistakes them as harmful foreign bodies, releasing exaggerated antibodies to fight the protein. In the cascade of inflammatory response, one manifests clinically with allergic symptoms. 

As most parts of condoms are made up of latex, this can affect a person’s sexual well-being.

Why do I have a latex allergy?

In allergy, a person can develop three mechanisms of response to rubber/latex.

  1. IgE-mediated allergic response (type 1 allergic reaction): upon exposure to latex protein via contact, the immune system generates an antibody known as immunoglobulin E (IgE) that causes a cascade of inflammatory response. Clinically, one presents with acute allergic symptoms.
  2. Contact Dermatitis (Type 4 allergic reaction/cell-mediated delayed allergic reaction): as the name suggests, upon exposure to the latex protein 24 to 48 hours, the body is sensitised by the latex protein leading to an allergic reaction.
  3. Irritant Contact Dermatitis: this can be seen due to repeated close contact with the latex protein, which leads to skin irritation.

Based on the allergic mechanisms discussed above, it becomes evident that condom latex allergy may develop gradually with prolonged use, as the body becomes increasingly sensitised to the latex protein upon repeated exposure.

rashes hives
Contact dermatitis is a symptom of allergy.

What are the symptoms of latex condom allergy?

In comparison between men and women, women tend to experience more severe symptoms of latex condom allergy given the thinner mucous membrane of the vaginal tract with a larger surface area of contact and absorption of the allergens from the condom.

Thankfully, most patients with condom latex allergy present with mild allergic symptoms over the contact surface (genital region) of the condom.

Common symptoms of latex allergy include:

In some cases, symptoms may involve systemic symptoms such as wheezing, watery eyes, runny nose, facial swelling or flushing, and rashes over the body.

Rarely can one develop anaphylactic symptoms within seconds to minutes upon exposure to latex.

However, it is still important to be aware of severe allergic symptoms.

Severe symptoms of latex allergy include: 

In such a dire situation, please go to the emergency department immediately as anaphylaxis can be life-threatening, and it is a completely reversible condition if prompt treatment is given.

difficulty breathing
Go to the hospital immediately if you are experiencing shortness of breath.

What is a latex-fruit allergy? 

Interestingly, about 30-50% of people with latex allergies are predisposed to have allergies to certain fruits. This is in view of the cross-reactivity of the allergen from latex and fruits. The body, being sensitised to the protein in the latex, mistakenly recognises the protein in certain fruits, causing a similar allergic reactions in the case of latex allergy. This is known as latex fruit allergy.

One may be more allergic to fruits such as avocado, banana, kiwi, peach, tomato, potato, passion fruit, and bell pepper. 

If you are concerned about latex or fruit allergies, you can reach out to your doctor, who you are comfortable with, for further evaluation. In certain cases, you may be offered an allergy blood test (RAST test) to confirm your latex and fruit allergy.

Is it possible that I am allergic to other chemicals in the condom rather than latex?

Yes, it is possible. One can be allergic to chemicals in the condom such as spermicide (nonoxynol-9), lubricants that have paraben, propylene glycol, glycerin etc. Symptoms associated with sensitivity to other chemicals in condoms are similar to latex condom allergy, such as redness, itch, burning, and swelling over the genital region. 

Often, the symptoms can be challenging to differentiate from a latex allergy or even other differentials such as sexually transmitted diseases (STDs). It is worth speaking to your healthcare providers about your possible concern about allergy to the components of condoms and allow your physician to evaluate further.

latex allergy singapore
Talk to your doctor about your latex allergy.

If I have an allergy to latex condoms, what are my other options for barrier contraception?

You can consider latex-free condom alternatives such as:

When should I consider seeing a doctor if I am concerned about latex condom allergy?

If you are feeling uncomfortable down below following intercourse, with symptoms such as itching, discharge, pain, redness, swelling, rash, or fever that doesn’t resolve, you should reach out to your doctor for further checkup.

What can my doctor offer me?

Your doctor will obtain your relevant medical and sexual history and then offer a relevant physical medical checkup. In the event of a concern of condom latex allergy, your doctor may offer you an allergy test, such as a RAST blood test, to detect any latex antibodies present in your body. Depending on individual risk of exposure, if there is concern of a concurrent infection, your doctor may discuss with you further STD screening tests.

How is latex condom allergy treated?

In the case of latex condom allergy, avoidance of culprit allergen is key. Your doctor may counsel you on various alternative options of latex-free condoms or other effective modes of contraception.

Antihistamines and topical steroids may be offered for localised latex condom allergic symptoms. In life-threatening allergy reactions, urgent medical attention with an adrenaline injection may be required to reverse the allergy.

Take home message for today:

References

  1. Mahdy H, Shaeffer AD, McNabb DM. Condoms. [Updated 2023 Apr 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470385/
  2. S Wagner et al. The latex-fruit syndrome. Biochem Soc Trans.  2002 Nov;30(Pt 6):935-40.
  3. Turjanmaa K. Turjanmaa K. Rubber gloves and condom cause immediate hypersensitivity. Duodecim.1989;105(23-24):1905-8. 
  4. Rosenberg MJ, Waugh MS, Solomon HM, Lyszkowski AD. Rosenberg MJ, et al. The male polyurethane condom: a review of current knowledge. Contraception. 1996 Mar;53(3):141-6
  5. D A Levy et al. Allergy to latex condoms. Allergy.  1998 Nov;53(11):1107-8.
  6. C P Hamann et al. Cutis. Update: immediate and delayed hypersensitivity to natural rubber latex. Cutis. 1993 Nov;52(5):307-11

In Singapore, egg allergy is one of the most common food allergies seen in young infants and children, together with cow’s milk allergy. A person develops an allergic reaction to eggs when the body inadvertently recognises egg proteins as a foreign or dangerous substance and mounts an exaggerated immunological response. 

The clinical manifestation of egg allergy can range from mild symptoms such as hives, rhinitis, and eczema to severe life-threatening allergic reactions such as anaphylaxis. Thankfully, most people with an egg allergy experience mild symptoms, and most children who experience an egg allergy tend to outgrow the symptoms over time.

egg allergy child
Children tend to outgrow an egg allergy.

What are the symptoms of an egg allergy?

The allergic response to eggs may vary from one person to another. Symptoms may occur within minutes or hours following consuming eggs or food which contains eggs. 

Most allergic symptoms are mild, though occasionally, one can develop life-threatening symptoms following the consumption of eggs. Allergy symptoms can affect multiple organs of the body:

Dermatological symptoms

Respiratory symptoms

Gastrointestinal symptoms

Rarely, one may develop anaphylaxis. This is a very serious medical condition that warrants immediate medical attention as one can succumb to the allergy.

egg allergy symptoms
Individuals with an egg allergy may experience hives or wheal skin lesions after consuming eggs or foods that contain eggs.

Symptoms are systemic; always remember the algorithm A-B-C:

If you or your loved ones develop any symptoms of A-B-C, please seek medical assistance immediately. Don’t delay; anaphylaxis is reversible if managed promptly.

What are the risk factors for developing an egg allergy?

egg allergy
Egg allergies are more common in individuals with a family history.

Which part of the egg causes the allergy? The white or the yolk?

The proteins found in an egg's white and yolk can cause an allergic reaction, though it is far more common for one to be allergic to the white of the egg.

Allergen proteins in the egg white, such as ovomucoid, ovalbumin, ovotransferrin, and lysozyme, are allergens commonly associated with egg allergies.

The egg yolk contains a protein known as alpha-livetin. This protein plays a role in an allergy condition known as bird-egg syndrome. This is a condition where a person is firstly exposed and sensitised to airborne related bird allergens, with a subsequent secondary exposure and sensitisation to egg yolk protein. Patients with this medical condition present with respiratory symptoms such as asthma or rhinitis following exposure to the bird and eating the eggs.

So why do we develop an allergic reaction from the egg proteins? Simply put, the ability to cause allergy to the protein can be correlated to their resistance against the gut's digestive enzymes and heat. The more robust the egg proteins are against heat and digestive enzymes, the more likely they can elicit an immune response. This is seen in people who are allergic to ovamucoid protein, which is more ‘heat-stable’ and ‘stable against digestive enzymes’, where they may have more persistent allergy symptoms than people who are allergic to other types of egg proteins.

bird-egg syndrome allergy
Bird-egg syndrome causes individuals to develop respiratory symptoms such as asthma and allergic rhinitis after exposure to birds or their eggs.

When should I see my doctor regarding egg allergy?

If you develop the allergy symptoms discussed above and are concerned about egg allergy, you can visit your doctor to test for the possible allergy. Your doctor may work with you to review the potential allergies based on your symptoms and advise accordingly.

How can I diagnose an egg allergy?

Diagnosis of egg allergy is based on a strong history and physical symptoms of allergy and the positive correlation with egg consumption.  Depending on the individual case, your doctor may advise you for allergy tests in the form of skin prick or blood (RAST) tests to evaluate the possible allergy further. 

There are available allergy tests for the whole egg, the egg white, the egg yolk, or even the individual egg proteins. You may be advised to temporarily eliminate eggs from your diet and reintroduce them back to your diet later under medical guidance.

How can I treat an egg allergy?

The only treatment for food allergies is avoiding the food particles that cause the allergy- in the case of egg allergy –  to avoid eggs.

For mild symptoms, your doctor may prescribe antihistamines and other symptomatic relievers to manage your allergy symptoms. In those who are at risk of anaphylaxis, your doctor may prescribe you an adrenaline injection pen to use in dire circumstances. 

In the case of food allergy, it is important to read food labels before consuming food. While eating out, it is always important to remind the kitchen/chef of your food allergy. If you are breastfeeding and your child has an egg allergy, do avoid food that contains eggs, as the allergic protein can be passed on through breast milk to your child.

breastmilk allergies
Food allergens may pass to your baby through breast milk.

Is a well-cooked/ processed egg suitable for a person with an egg allergy?

Medical literature reveals that patients with an egg allergy may be able to tolerate highly heated or baked/processed eggs (muffins/cookies). This is due to the possible denaturing of the allergenic protein by high heat, allowing patients to tolerate food with eggs. However, it is difficult to identify such a group of patients unless the patients are determined through an oral food challenge test

This should be practised cautiously as severe allergy can occur during oral food challenge tests. You are advised to discuss with your doctor before trying processed or high-heated eggs if you have a history of egg allergy.

Vaccination Safety and Egg Allergy

What have I learnt today…

References:

  1. Caubet JC, Wang J. Current understanding of egg allergy. Pediatr Clin North Am. 2011 Apr;58(2):427-43.
  2. Konstantinou GN, Giavi S, Kalobatsou A, et al. Consumption of heat-treated egg by children allergic or sensitised to egg can affect the natural course of egg allergy: hypothesis-generating observations. J Allergy Clin Immunol. 2008;122(2):414–5.
  3. Lemon-Mule H, Sampson HA, Sicherer SH, et al. Immunologic changes in children with egg allergy ingesting extensively heated eggs. J Allergy Clin Immunol. 2008;122(5):977,983, e1. 
  4. https://www.cdc.gov/flu/prevent/egg-allergies.htm
  5. https://www.healthhub.sg/live-healthy/influenza_vaccine_for_your_child#:~:text=The%20influenza%20vaccine%20is%20also,tenderness%20at%20the%20injection%20site.
  6. National Advisory Committee on Immunization (NACI). Egg allergy and MMR vaccine: New recommendations from the National Advisory Committee on Immunization. Can J Infect Dis. 1996 Sep;7(5):289-90.
  7. https://www.cdc.gov/yellowfever/qa/index.html#novaccine

Real-life scenario: You may have had an amazing trip overseas, met terrific people, and explored new places, but you start noticing skin rashes [1] and itching upon returning home. Could this be due to bedbug bites, especially since there is a major global resurgence? Or could this be something else — like an STD instead?

In this article, we delve into bedbug bite symptoms, ways to manage these symptoms, and possible differentials besides diagnosing bedbug bites.

bed bug
Bed bugs commonly come out during the day to feed on a person’s skin and blood.

What are bedbugs?

Bedbugs, also known as Cimex lectularius, are tiny, brown-reddish insects [2] that hide in the crevices of mattresses, bed frames, headboards, cupboards, or box springs. Although they can come out any time of the day, they tend to creep out at night to feed and suck on the victim’s skin and blood. Bedbug bites and saliva can trigger an immune response in the victim’s skin, leading to an inflammatory response.

Bedbug bites are more common [3] in people with poorer hygiene, lower socioeconomic status, and living in homeless shelters, hotels, and/or hospitals.

In recent months, we have noted a global resurgence of bedbug infestations affecting major cities, including Paris, London, and New York. The adventurous hitchhiker is also making progressive headlines of infestations in Asia countries, including Korea and our beloved home, Singapore.

What are the signs and symptoms of bedbug bites?

In more severe cases, one may develop a secondary immune allergic reaction, known as an ‘id’ reaction, with presentation of the following:

If you are experiencing a skin rash and are uncertain of the cause of your condition, do reach out to your physician for evaluation and treatment. Bedbug bites are a treatable condition.

bed bugs rash
Rashes linked to bed bug bites may spread to other body parts.

When should I see a doctor for bed bug bites?

If you are experiencing any bedbug bite or allergic symptoms stated above or are concerned about other differentials such as STDs, please contact your doctor for further evaluation.

What should I expect when I see my doctor for bed bug bites?

Your doctor will obtain a relevant history regarding your rash. Your social history, including recent travel history and sexual history, maybe enquired to aid the diagnosis. Your doctor will then examine the rash, which may involve examining your mouth, eyes, or even your genital region. 

Depending on individual conditions, your doctor may offer skin tests in the form of a scrape or swab. If an infection is suspected, further tests in the form of blood and/or urine tests may be offered.

Where can I find bedbugs?

As their name suggests, bedbugs tend to thrive near our sleeping environment. You may be able to find bedbugs infesting [5] the bed, mattresses, headboards, box springs, clothing, cabinet, luggage, carpet, or boxes near your bed.

A recent travel history to bedbug-infested cities may increase the risk of contracting bedbug bites. Individuals who live in dormitories, sheltered homes, cruises, hotels, and/or trains may also be slightly predisposed to bedbug bites.

mattress bedbugs
The bed and mattresses can be infestation spots for bed bugs

Are bedbugs a type of STD? What are the differences between the two?

Bedbug bites are not STDs. As the name suggests, bedbug bites are due to insect bites leading to a skin inflammatory response. In STD, the infection is contracted [6] from sexual intercourse, such as in the form of oral, vaginal, or anal sex. Bedbug bites are not transmissible from one human to another. STDs can be passed on between people if they are not treated and there is sex involved.

Can bedbugs spread STDs after biting a person with STDs?

Fact of the day: bedbugs do not carry and spread STDs. STDs are transmitted through sexual contact and passed between people. Having said that, rashes caused by STDs occasionally mimic rashes from a bedbug bite. Hence, it is important to consider screening for STDs if there is a risk of exposure.

What are the similarities between bedbugs and STDs?

STD rash (by condition)Bedbug bites rash
SyphilisWidespread red bumps, scaly and itchy. Can mimic any skin condition.Widespread discrete red bumps, itchy, can be scaly due to repeated scratching
HIVFaint red dots which blanche when touchedRed bumps which tend to be raised, palpable, and itchy but can mimic HIV rash
ScabiesRed itchy bumps, excoriated, with mite ‘burrows’ seenRed, itchy bumps, excoriated, can be linear in appearance – like scabies
Herpes Grouped or clustered blisters (fluid-filled lesions)In severe bedbug bites, blisters can be seen as part of an allergic response or as a result of intense scratching
Chlamydia GonorrhoeaCan occasionally present with pustules (white) bumpsLess commonly present with pustules- though this may occur as a result of secondary bacterial infection

Bear in mind the appearance of the rash for both bedbug bites and STDs can be medically quite technical. Sometimes, even a trained pair of eyes can find it difficult to differentiate between them.

The suspected differential can be confirmed or ruled out through appropriate tests. Discuss with your doctor whether appropriate tests are required for your skin presentation.

How are bedbug bites treated?

Thankfully, most bedbug bites are not dangerous. Treatment includes antihistamines, topical steroids, and soothing moisturiser. In severe cases of bedbug bites, especially with an allergic reaction, your doctor may prescribe a short course of oral steroids to clear off the symptoms. Oral antibiotics may be considered for individuals with secondary bacterial infections.

topical treatment
Topical steroids can be used to treat bedbug bites.

How can I get rid of bedbugs?

Affected clothing or objects should be washed at a high temperature, around 60℃ and tumble dried at a high temperature. Placing affected items in an extremely cold environment, such as the freezer (-18℃), is another method to eradicate bedbugs.

You may consider contacting pest control services to eradicate bedbugs from your living space effectively.

How to prevent bedbug bites?

The fun fact of the day: bedbugs tend to bite over exposed areas of the skin; they seldom burrow beneath clothing. Wearing covered/long-sleeved clothing or pyjamas may reduce the chances of getting bitten by bedbugs.

When you are living abroad or in a hotel, check for bedbugs! Inspect the crevices of the bed(s) or mattress(es) for possible bedbugs or bedbug particles. Place your bags and luggage on the dressers or luggage rack, keeping them away from the bed. If you suspect bedbugs are in your belongings after travelling, you can consider placing them in a plastic ziplock bag and sealing them up.

When you return home from abroad, unpack your luggage or bags on concrete/solid surfaces such as the bathroom floor, garage, or at the entrance.

bedbugs prevention
Place your luggage on a raised hard surface when staying at hotels.

Are bedbugs still bugging you after reading this article?

It is reassuring to know that there are effective medical options for managing the symptoms secondary to both bedbug bites and other disguised diagnoses such as STDs. Being safe is key. Reach out to your medical physicians for further consultation and to confirm your skin diagnosis.

References

  1. “Skin Rash and Lesions – General - STI Guidelines Australia,” STI Guidelines Australia, November 9, 2021, https://sti.guidelines.org.au/syndromes/skin-rash-and-lesions-general/.
  2. Ennis AC, Pearson-Shaver AL. Bedbug Bites. [Updated 2023 Jul 31]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538128/
  3. “Some Singapore Pest Control Firms Report Increase in Bedbug Infestations, Expect More to Come,” CNA, 2023, https://www.channelnewsasia.com/singapore/bed-bugs-treatment-awareness-singapore-hotels-homes-dormitories-3916956.
  4. Doggett SL, Dwyer DE, Peñas PF, Russell RC. Bed bugs: clinical relevance and control options. Clin Microbiol Rev. 2012 Jan;25(1):164-92. doi: 10.1128/CMR.05015-11. PMID: 22232375; PMCID: PMC3255965.
  5. “Whats-Bugging-You,” Healthhub.sg, 2016, https://www.healthhub.sg/live-healthy/whats-bugging-you.
  6. “Sexually Transmitted Diseases - Information from CDC,” 2024, https://www.cdc.gov/std/default.htm.

Pets are man’s best friend. What if you have allergies and have always wanted a cat or a dog? These days, we commonly hear the term ‘hypoallergenic pets’. Is this truly the solution for pet lovers with long-standing allergy symptoms? 

This article explores the term 'hypoallergenic pets' and clinical and non-clinical treatment options for managing pet allergic symptoms.

hypoallergenic pets
Do hypoallergenic pets really exist?

How does a pet cause allergic symptoms in humans? 

An allergic reaction is an exaggerated body response towards an innocuous substance upon exposure to the substance through the respiratory system, skin or mucous membrane. In the case of pet allergies, it is often not the ‘dander or fur’ of the pet that causes the allergic reaction but rather the protein in the pet’s urine or saliva. These proteins can attach themselves to the pet dander. When the hair is shed periodically, the particles will be disseminated onto the surrounding environment, such as the carpet, linen, bed, sofa, furniture, etc. When a person is in contact with the particles through direct touch onto the skin or mucous membrane or breathing, the body mounts an inflammatory exaggerated immune response leading to allergic symptoms.

To make things worse, pet danders also create an environment to capture various airborne particles such as dust mite particles, mould spores, or pollen that may also potentiate allergic reactions. 

What does it mean by 'hypoallergenic pet'? 

Pets such as cats and dogs have been marketed as ‘hypoallergenic breeds'. Essentially, this means the hypoallergenic pets shed less than other ‘normal breeds’. Less dander shedding will lead to less or minimal protein allergens released in our living environment, hence reducing the risk of allergies. 

However, it is worth noting that even hypoallergenic pets are not entirely ‘shed-free’; hence, they are not ‘allergen-free’ either, and one can still develop allergic symptoms. Also, the length and amount of the animal fur do not determine the allergic response. Allergic symptoms can still occur even if a person obtains a hypoallergenic pet.

sphynx cat
It is a common misconception that hairless breeds of cats are hypoallergenic.

What is the common allergic response due to pet dander?

Allergy can present a spectrum of symptoms affecting various organs of the affected person. The severity of individual allergic symptoms varies from person to person – some may present with mild symptoms. In contrast, others may develop symptoms that disrupt their daily function or require clinical intervention.

Allergic reactions from pet dander allergies include:

Pet dander allergic symptoms are usually exacerbated when a person is in contact with the animal. However, the allergic symptoms frequently persist even when the pet is no longer physically present. This is due to the remnants of the dander in the surrounding environment and the impracticality of removing or altogether avoiding the allergen (dander).  

pet allergy
Pet allergy symptoms include sneezing, coughing, wheezing, itching, watery eyes, etc.

How can I confirm my allergies?

You are advised to see your doctor, who will obtain a medical and social history to understand the possible correlation between the triggering allergens and your symptoms. Depending on your condition, your doctor may offer you a skin prick test or IgE RAST blood test to rule in or rule out the concerning allergens.

When pet dander allergies are of concern, your doctor may offer an allergy test to test for pet dander, dust mites, mould and other common airborne allergens. Your doctor can advise you further on treatment and management of the allergies from the results.

How can I manage pet dander-related airborne allergies at home?

Here are some tips to reduce pet allergens in your living environment: 

saliva pet allergy
Saliva contains a protein that causes pet allergies.

Are there medical treatments to manage pet dander allergies?

Patients do commonly seek medical support for pet allergies for two reasons:

Thankfully, there are effective medical treatment options to manage pet allergy symptoms. 

Your doctor must understand your history and the correlation of the allergy symptoms with the pet. Depending on individual risk of exposure, your doctor may offer an allergy test in the form of a skin prick test or blood RAST test to confirm the pet allergies or possible concurrent air-borne allergies such as dust mite or mould allergies. 

Your doctor may offer symptomatic medications such as antihistamines, steroidal tablets, topical creams, nose sprays and inhalers to relieve your symptoms immediately. In patients with positive allergy tests for pet allergies or airborne allergies, your doctor may discuss the medical option of immunotherapy

The role of immunotherapy in managing pet dander allergies

The idea of immunotherapy is re-educating and re-setting the immune system. As mentioned, in allergy, the body’s immune system develops an exaggerated inflammatory response towards a generally harmless substance. In immunotherapy, one strives to re-challenge the immune response with repeated small dose exposure of an allergen to the body and de-sensitize the immune response towards the allergen. Over time, this leads to a down-regulation of the immune response against the allergen, significantly reducing or resolving the clinical allergic symptoms. 

When used under the proper supervision of a physician, immunotherapy is safe and is a clinically evidence-based long-term treatment for airborne allergies. It has been proven to alleviate and treat allergic rhinitis, allergic conjunctivitis, and asthma associated with air allergens. Immunotherapy reduces reliance on symptomatic or 'rescue' medications in allergy patients and minimises the patient's medication burden in the long run. With allergy symptoms under control, the affected person's quality of life can be improved.

Final word for pet lovers and allergies…

If you struggle between your allergic health and your love for your pets, consider speaking to your physician to understand more about allergy testing and immunotherapy treatment. 

References

  1. Virtanen T. Immunotherapy for pet allergies. Hum Vaccin Immunother. 2018 Apr 3;14(4):807-814. doi: 10.1080/21645515.2017.1409315. Epub 2017 Dec 21. 
  2. Persaud Y, Memon RJ, Savliwala MN. Allergy Immunotherapy. [Updated 2023 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK535367/
  3. Corren J. Allergic rhinitis and asthma: how important is the link? J Allergy Clin Immunol. 1997 Feb;99(2):S781-6. 
  4. Klimek L, Pfaar O, Bousquet J, Senti G, Kündig T. Allergen immunotherapy in allergic rhinitis: current use and future trends. Expert Rev Clin Immunol. 2017 Sep;13(9):897-906. 
  5. Şahin E, Bafaqeeh SA, Güven SG, Çetinkaya EA, Muluk NB, Coşkun ZO, Lopatin A, Kar M, Pinarbasli MO, Cingi C. Mechanism of action of allergen immunotherapy. Am J Rhinol Allergy. 2016 Sep 1;30(5):1-3.
  6. Oktemer T, Altıntoprak N, Muluk NB, Senturk M, Kar M, Bafaqeeh SA, Bellussi L, Passali D, Cingi C. Clinical efficacy of immunotherapy in allergic rhinitis. Am J Rhinol Allergy. 2016 Sep 1;30(5):4-7.

‘Doctor, there are tiny bubbles on my palms, and they are extremely itchy. I cannot sleep! Am I allergic to something?’ This is a common encounter in the consultation room. This article explores hand eczema – a common skin inflammation and its correlation with our diet.

What is Pompholyx/Dyshidrotic eczema?

Pompholyx is a type of eczema, also known as dyshidrotic eczema. It is a type of skin condition that affects the hands and feet. Eczema is a chronic inflammatory skin condition that causes intermittent itchy red rashes (of various forms) that can occur on any part of the skin. In pompholyx, eczema mainly targets the palms of the hand and soles of the feet. It is commonly seen in women and those under the age of 40.

hand eczema
Hand eczema is commonly seen in women and those under 40.

What does pompholyx/dyshidrotic eczema look like?

In dyshidrotic eczema, one presents with deep-seated tiny, multiple watery blisters that are immensely itchy and uncomfortable over the hands and feet. Over time, the blisters can become weepy, especially when broken, and one will be susceptible to bacterial infection. This further causes skin inflammation with swelling, discomfort, pain and itch. The weepy affected area will eventually dry out, leaving the skin dry and flaky with painful fissures and cracks. Patients with chronic symptoms of dyshidrotic eczema can have abnormal nail folds (skin surrounding the nails) and nail changes.

dyshidrotic eczema
Flaky and cracked skin is common in individuals with hand eczema.

What are the possible triggers for pompholyx/dyshidrotic eczema?

The exact reasons for developing pompholyx remain unknown. Patients who develop dyshidrotic eczema are generally more atopy (sensitised to the surroundings – be it environment or food). They can be associated with atopic eczema, allergic rhinitis, and asthma and may have a family history of atopy as well.

Potential triggers of dyshidrotic eczema include the following:

As individual patients may have different triggers and genetic predispositions, it is worth speaking to your trusted doctor regarding your symptoms, and your doctor can guide you further on the possible triggers in your case.

Food allergies and pompholyx/dyshidrotic eczema

Although the clinical evidence between eczema and food allergies remains much to be elucidated, it is worth exploring the relationship between dietary intake of nickel and dyshidrotic eczema.

Nickel is one of the common elementary microminerals found in most of our staple diets. It is clinically observed that nickel in diet can predispose an atopic person to dermatitis (skin inflammation), with the hands being one of the common sites associated with nickel dermatitis. A diet low in nickel has shown improvement in eczema conditions. Regarding pathophysiology, exposure to nickel may lead to ‘sensitisation’ of the body against nickel. Over time, with repeated exposure to nickel from the diet, the body develops an allergic reaction that manifests as skin inflammation.

dietary nickel allergy
Dietary nickel is present in many foods, which may make it challenging to eliminate nickel from your diet completely.

Most dietary nickel comes from plant-based food. Food that are high in nickel content includes chocolate, oatmeal, rye, buckwheat, tea, liquorice, chickpeas, soya, nuts, almonds, lentils and legumes, broccoli, onion, garlic, leafy green vegetables, canned and processed food. (This is pretty much everything we eat daily!)

As nickel can be found in nearly all food, completely eliminating nickel from our daily diet is not feasible. However, the risk of exposure and sensitising a person with nickel in the context of dermatitis can be reduced with prudent food selection and a diet with low nickel concentration.

The caveat is that a low nickel diet does not guarantee a complete clear-up of dermatitis. Instead, a mindful diet practised over time may be associated with lesser or milder eczema flare-ups. 

You can speak to your doctor to understand further the association between food allergy and your skin condition. Depending on individual risks and skin conditions, your doctor may discuss further on allergy testing to evaluate further.

What may be expected when you see your doctor for dyshidrotic eczema?

Your doctor will obtain a relevant history of your symptoms and examine the rash on your hands and feet. Depending on the presentation and index of suspicion, your doctor may offer you other tests such as bacteria or fungal swab/scrape test or even scabies/syphilis screen to rule out other differential. If there is an allergy concern, your doctor may even offer you a skin prick test or blood RAST test. Do visit your doctor if you have a rash that does not resolve.

What will happen if I don’t treat dyshidrotic eczema?

Generally, dyshidrotic eczema is not a life-threatening condition. However, chronic severe eczema is known to be associated with significant reduction and impairment of quality of life. This is because the affected inflamed skin will become flaky and dry, and open wounds/bleeding may occur. The associated itch with dyshidrotic eczema can be intense and unbearable, which can impede the daily function of the affected body part.

feet eczema
If left untreated, dyshidrotic eczema can result in an intense and unbearable itch, impeding the daily function of the affected area.

What may mimic pompholyx/dyshidrotic eczema?

As dyshidrotic eczema presents with blisters over the hands and feet, the condition also mimics various infective conditions such as herpes, syphilis, or even hand-foot-mouth disease. Other differentials that have a similar appearance to dyshidrotic eczema include allergy/irritant skin inflammatory conditions and autoimmune blistering skin conditions.

It is worth letting your doctor look at the rash that affects your hands and feet. The medical treatment differs depending on the individual medical condition. If you are experiencing severe pompholyx/dyshidrotic eczema, see a healthcare professional rather than self-medicating with various ointments, creams, and over-the-counter medication that may worsen the condition further.

What is the treatment offered for pompholyx/ dyshidrotic eczema?

Treatment for pompholyx/dyshidrotic eczema depends on various factors such as severity, underlying conditions, and the individual's overall health. In general, treatment involves the following: 

eczema steroids
Topical steroids might be prescribed to help alleviate your symptoms.

In severe dyshidrotic eczema or recalcitrant cases, second-line treatment such as phototherapy or oral immunosuppressants may be required to control the symptoms. You are advised to speak to your doctor regarding the symptoms and treatment you have tried. While the above is a general guide to treating dyshidrotic eczema, your doctor may tweak the treatment regimen to suit your condition and needs.

What should I do at home if I have pompholyx/dyshidrotic eczema?

If your pompholyx/dyshidrotic eczema is mild or you would like to try and manage your symptoms, consider the following:

Some note-worthy thoughts…

Some people suffer only once in a lifetime episode of dyshidrotic eczema/pompholyx. Unfortunately, others may have a recurring and frustrating journey of skin inflammation. Good patient education on this common benign skin inflammatory condition is key for managing their skin with appropriate treatment and minimum exposure to possible triggers, including food triggers.

If you would like to learn more about eczema, dyshidrotic eczema, food allergy, or allergy in general, do feel free to reach out to your trusted clinician

References

  1. Sharma AD. Low nickel diet in dermatology. Indian J Dermatol. 2013 May;58(3):240. 
  2. Guillet MH, Wierzbicka E, Guillet S, Dagregorio G, Guillet G. A 3-Year Causative Study of Pompholyx in 120 Patients. Arch Dermatol. 2007;143(12):1504–1508. 
  3. Sharma AD. Disulfiram and low nickel diet in the management of hand eczema: A clinical study. Indian J Dermatol Venereol Leprol. 2006;72:113–8.
  4. Gawkrodger D J, Cook S W, Fell G S, Hunter J A. Nickel dermatitis: the reaction to oral nickel challenge. Br J Dermatol 1986: 115 33–38.
  5. https://www.nhs.uk/conditions/pompholyx/
  6. https://patient.info/skin-conditions/atopic-eczema/pompholyx
contact dermatitis
Contact dermatitis presents itself as distressed skin inflammation.

What prompted this article is an episode of distressing skin inflammation by one of the authors of this blog. For some background information, this writer is a creature of repetitive habits without a shadow of a doubt. After a recent change in one of the facial topical products, the skin over their face started to become red, inflamed, painful, and very itchy after just three days of use.

The skin is the largest organ in our body. While building a good skin barrier layer takes months to years, acute contact dermatitis can lead to an evident and sudden skin deterioration due to an acute skin barrier breakdown. This can happen to anybody.

In this article, we delve into the types of contact dermatitis, causes of the condition, ways to minimise developing contact dermatitis, and tips to rescue the affected skin.

What is contact dermatitis?

As the name suggests, contact dermatitis is defined as a skin inflammatory condition due to direct contact with the application of substances onto the skin’s surface. Contact dermatitis can occur on any part of the body, though the hands, face, and feet are frequently affected.

There are two types of contact dermatitis: irritant contact dermatitis and allergic contact dermatitis.

dermatitis on feet
The feet are a commonly affected area for contact dermatitis.

What are the symptoms of contact dermatitis?

Patients with contact dermatitis tend to present with:

What causes contact dermatitis?

The skin rash response during contact dermatitis is a negative inflammatory response from one or more external agents in touch or contact with the skin. This leads to a vicious cycle of weakening the skin barrier, inflammation over the skin, and further impairing the skin's protective layer.

In irritant contact dermatitis, the external agents present as irritants that corrode the normal skin barrier, leading to a skin inflammatory response. The most common irritants include water, strong chemicals (acid or alkalis), detergents, solvents, and abrasives (repeated friction). Strong irritants cause immediate breakdown of the skin barrier, leading to a skin reaction within hours after exposure. Generally, after repetitive and cumulative exposure to irritants over months and years, individuals may notice a more subtle skin reaction over time.

In allergic contact dermatitis, an interesting delayed allergic response takes place. This is known as a type 4 hypersensitivity allergic reaction. To begin with, patients with allergic contact dermatitis tend to have eczema with a weaker overall skin barrier. The introduction of external substances to the skin allows even easier access due to a weakened skin barrier. The substance is recognised by T-cells (immune cells) in the body, and upon repeated exposure to an external substance, the body’s immune system is reinforced and re-challenged with the external substances, leading to the development of an allergic skin response.

In allergic contact dermatitis, auto-sensitisation may even occur due to the awakening of the immune system, leading to a generalised spread of the rash. For example, a person may start with a facial rash due to direct contact with an allergen substance on the face; there may be a further spread of rash throughout the body and lower limbs due to auto-sensitisation.

Although irritant and allergic contact dermatitis is often discussed and explained separately, clinical practice commonly sees both causes occur simultaneously.

In irritant and allergic contact dermatitis, the skin barrier is compromised as the skin integrity is no longer at its best. This can be due to irritated skin or an allergic response. Subsequently, the skin will continue to deteriorate by a physical manifestation of increased damage.

skin rash
A rash can start at the face and spread to the rest of the body.

What are the common irritants and allergens that cause contact dermatitis?

Common irritants that cause contact dermatitis include:

Common allergens that cause contact dermatitis include:

If you are unsure of which of these are causing the above symptoms, a skin prick allergy test is a simple and accurate way to detect allergies. Allergy treatment will follow depending on the results.

makeup allergy
Makeup is a common allergen that can result in contact dermatitis.

What are the differences between irritant contact dermatitis and allergic contact dermatitis?

There are few tell-tail signs to differentiate the presentation between irritation and allergic contact dermatitis, though often the presentation may not be as clear-cut and may co-exist simultaneously.

 Irritant contact dermatitisAllergic contact dermatitis
Common sitesHandsExposed areas of the skin
Borders of skin rashStrictly confined to the exposure siteDemarcated borders, though, may spread to the peripherals and become generalised
Clinical symptoms (Acute)Intense stinging, pain, then eventually itchingItching, which can lead to pain
Clinical symptoms (Chronic)Itching and painItching and pain
Appearance (Acute)Redness, blisters, broken skin, erosions crust, and scalingRedness bumps, broken skin, crust, and scaling
Appearance (Chronic)Bumps, crust, scales, fissuresBumps, patches, scaling, crust
Timeline (Acute)Rapid, within hours after exposure12 to 72 hours after exposure

How is contact dermatitis managed?

The key to managing contact dermatitis is to eliminate and stop the offending substance(s) that plays a role in contact dermatitis.

In the real world, sometimes, complete elimination of the offending substance(s) may not be feasible due to the nature of certain occupations, or common irritants such as water or dust may not be wholly avoided. However, understanding the possible culprit(s) is important, as unnecessary exposure to irritants or allergens can be minimised. 

For example, in the case of water irritants, one should avoid repetitive unnecessary washing and use protective hand gloves when available and possible. If your workplace allows, consider protective gear or even a change of job roles to avoid exposure to offending substances.

Patients with contact dermatitis should be encouraged to repeatedly use moisturiser and barrier cream to maintain the skin barrier integrity. Avoid moisturisers with plant-based proteins, chemicals, or even fragrances. In active inflammation cases, topical steroids or even oral steroids may be required to manage the condition.

It is a knee-jerk reflex when the skin condition deteriorates, and we wish to troubleshoot it with various medications and creams on the affected area(s). Often, this may lead to further introduction of more irritants or allergens that potentially worsen inflamed skin. It is important to take a step back and remind ourselves that in contact dermatitis, less is more. Stop triggering substance(s) and avoid further aggravation!

steroids
Topical steroids may be prescribed to help manage the condition and its symptoms.

Can we manage contact dermatitis?

The outcome of contact dermatitis depends on whether the triggering external substance(s) can be avoided. If this is achievable, one can prevent further episodes of dermatitis. This may be challenging, as there may be more than one offending factor involved in contact dermatitis, and complete avoidance of the offending factors may be impractical.

Speak to your doctor if you are dealing with contact dermatitis. Your doctor can guide you further in evaluating the root of your condition and ways to manage the symptoms.

References

  1. Richard P. Usatine MD and Marcela Riojas MD. Diagnosis and Management of Contact Dermatitis. Am Fam Physician. 2010;82(3):249-255
  2. Johansen JD, Frosch PJ, Lepoittevin JP (eds). Contact Dermatitis 5th Ed. 2010; Berlin. Springer. A comprehensive detailed up-to-date reference book.
  3. Britton JE, Wilkinson SM, English JE, et al. The British standard series of contact dermatitis allergens. Br J Dermatol 2003; 148: 259-64.
  4. Johnston GA, Exton LS, Mohd Mustapa MF, Slack JA, Coulson IH, English JS, Bourke JF. British association of Dermatologists Guidelines for the management of Contact Dermatitis 2017. BJD 2017 Feb 176 (2) 317-329.       
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