Ageing and Allergies

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:

• mild bloatedness,
• nausea, 

to more severe symptoms such as:

• vomiting,
• diarhoea,
• or even severe life threatening symptoms of anaphylaxis. 

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:

• blocked nose, 
• watery nose, 
• repeated sneezing, 
• post nasal trip, 
• or itching of the nose and airway.

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.

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?

• Avoiding allergens — Avoiding any identified allergens is key in management of elderly allergies.
  
• Medications — Medications in the form of antihistamine, steroid may be offered to alleviate allergy symptoms. However, these medications need to be used in caution due to the side effects of medication in the elderly and possible drug interaction with other existing chronic medications. One, especially the elderly group should always consult their doctor before taking medications.
  
• Immunotherapy — Immunotherapy can be considered in certain types of allergies as a gradual desensitisation treatment against allergies and controlling the allergy symptoms over time. 

What have I learnt today?

• Allergies are becoming a common medical condition seen in the elderly as the global population ages.
  
• The body undergoes physiological and structural changes we grow older. This can result in immunosenescence and increase vulnerability towards allergens.
  
• Allergies in elderly tend to be under-diagnosed and difficult to be diagnosed as they may be masked by other geriatric medical conditions, or brushed away as part of ‘ageing’ and ‘fraility’.
  
• Allergy tests can facilitate identification of allergens in elderly.
  
• Treatment of allergy in elderly including avoidance of triggering allergens, symptomatic medications and use of immunotherapy in certain allergy conditions.
  
• Understanding and identifying allergies in the aged group are imperative in the management of symptoms, ensuring a better quality of life even when aged.

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.