Circadian Allergy: The Diurnal Fluctuation of Allergy

Ever wonder why our allergic symptoms vary in intensity in the day or at night? There is no change to our daily routine- came home, night in, brush teeth, climb up the bed, have the same good night sleep daily. Yet, out of the blue, the allergy symptoms hit with runny and blocked nose, sneezing, itchy eyes disrupting our beauty sleep. The symptoms persist, affecting our quality of sleep until the morning and slowly ease off eventually. And, this cycle just repeats itself day after day.

This is the diurnal changes of allergy. In this article, we delve into the science behind the rhythmic allergy symptoms and discuss on ways how we can manage the allergy.

What are the common circadian allergy symptoms that we can experience?

Allergy symptoms can be more pronounced at night and the wee part of the morning. 

Symptoms that one may experience include:

• Watery nose
• Blocked nose
• Watery and itchy nose
• Cough
• Wheezing
• Shortness of breath
• Skin itch
• Rashes over the skin

Circadian effect on Atopy Triad

The atopy triad is made of 3 main atopic conditions: allergic rhinitis, allergic asthma and atopic dermatitis.

While the atopic symptoms can occur any time of the day, one may notice more severe symptoms during sleep and early part of the morning.

Why is my allergy more severe at night?

• Particles that can trigger allergy in the air tend to accumulate and settle on our bed, linen, pillow over the course of the day. We can be highly exposed to these particles when sleeping at night.
• Daytime allergens such as pollen, pet fur can be transferred to our sleep environment.
• The sinus mucous can be gravitated towards certain parts of our upper airway causing breathing obstruction when we are lying flat.
• When the temperature drops at night, the change in humidity can result in irritation and inflammation of the upper airway leading to more mucous production.
• Our body produces more histamines (innate allergy chemical proteins) at night.

Relationship Between Body Circadian Clock and Allergy 

We know the key driver of allergy is a type of immune cells in our body known as mast cells. Mast cells can be found in our skin, soft tissues of the eyes, mouth, genital, respiratory system. When the mast cells are triggered either by external factors (such as allergens) or internal factors (such as hormones), they will release a cascade of inflammatory and chemical cells including histamines that can result in allergy symptoms

Research has shown that mast cells have an internal clock regulated by certain genes and external environment. Interestingly, the brain is engineered to perceive light, dark, human hormones, metabolism, infection and subsequently use this information to control the body's daily physiological function. The brain areas involving the hypothalamus and pituitary glands are responsible in controlling the circadian rhythm of mast cells- serving as a mast cell internal clock and its subsequent response upon activation. Any interference or changes to the mast cells internal circadian rhythm can result in abnormal immune response and eventual release of histamine and manifestation of allergy symptoms.

If the circadian rhythm is disrupted, are we more prone towards allergy?

Understanding the periodicity of allergy symptoms can aid modern clinical diagnosis and treatment management of allergy symptoms. Allergy treatment can be targeted towards the predicted circadian variation seen in allergic cases as we know that the internal biological clock plays important role in immune regulation.

In modern days, due to various sleep pattern, work, night shift, traveling, jetlag, eating habits, artificial lights, our internal clock can be disrupted. Our lifestyle can be out of sync with the internal clock leading to predisposition of allergy and difficulty in managing the symptoms. While studies are ongoing, medical literature encourages healthy management of lifestyle in combination to conventional medical treatment to realign our life and internal circadian rhythm while managing allergy.

What are the common allergens that can contribute to circadian allergy symptoms?

Allergens are proteins that can trigger an exaggerated immune response in our body following exposure –be it through inhalation, touching or even consuming.

Allergens that are responsible for circadian changes of allergic symptoms tend to be air-borne allergens including

• Dust mites
• Mold
• Pollen and grass
• Animal dander
• Cockroach particles

How can we find out the culprit allergen(s) that affect our circadian allergy?

If you have concern of circadian allergy, you can consider consulting your healthcare providers. A strong association history of nocturnal and cyclical allergy symptoms is suggestive of the diagnosis. The diagnosis can be further confirmed with allergy tests in the form of skin prick tests and blood RAST tests. Both tests can be done safely in outpatient settings.

What happens if we don’t manage our circadian allergy?

The symptoms continue to propel cyclically, disrupting our sleep quality. Overtime, one may develop chronic fatigue, morning headache, poor energy level, morning sleepiness or drowsiness, causing poor our daily function and work performances.

Poor control of allergy also results in poorer control of general atopy. One may notice increase intensity of allergic rhinitis symptoms and possible concurrent asthmatic symptoms. Those with atopic dermatitis may notice poorer skin condition with frequent exacerbations, itch or even susceptibility to skin infections.

Furthermore, ongoing nocturnal allergic symptoms that are not properly managed can contribute to sleep apnea. The profound allergic symptoms can clog up and obstruct a person’s airway during sleep causing temporary cessation of breathing (apneic) episodes. This result in inadequate air passing through the upper airway to the lungs. As time goes by. 

this can put a strain to the thorax and breathing muscles, the lungs and even the heart. 

How can we manage circadian allergy?

Lifestyle management

• One may consider sleeping with 1-2 pillows, tilting the head at an angle of 30-45 degrees from the bed. This allows lesser gravitational effect on the sinus mucous, less post-nasal drip and better breathing of the upper airway.
• Bedsheets, pillow case, linen, carpet should be changed regularly, washed at high temperature (more than 60 degrees) and air under the sun.
• Use of air purifier with HEPA filter at night may reduce airborne allergen particles.
• Avoid sleeping with your pets. 
• Showering before bed can reduce allergen particles that are present on your body and hair.

Medical management

• Night time allergy symptoms can be managed with medications including antihistamines, steroids, inhalers, nose sprays. 
• In those with poorly controlled allergy symptoms, desensitization treatment with targeted immunotherapy can be considered. Immunotherapy can be used to re-educate the body’s immune system to downregulate allergic response towards culprit allergens. Immunotherapy has also potential in resetting the internal biological clock controlling mast cells, thereafter improving overall allergic symptoms.
• Diagnosing and managing concurrent obstructive sleep apnea is useful as part of the holistic management of night time airway/ allergic symptoms. 

What have I learnt today?

• Allergy symptoms can fluctuate and can be worse at night.
• Our innate biological circadian clock controls the potential release of allergy immune cells causing more pronounce allergy symptoms at night.
• The body’s circadian clock can be disrupted by modern lifestyle, predisposing one towards allergies.
• Airborne related allergens can be responsible to nocturnal allergic symptoms.
• Nocturnal allergy can be diagnosed with clear association history between allergic symptoms and diurnal nature of symptoms.
• Allergic tests can further facilitate the diagnosis of circadian allergy. 
• Further to lifestyle adjustment, symptomatic medical treatment, immunotherapy and management of sleep apnea are effective in managing circadian allergy.

Contact DB Clinic

If your allergy symptoms seem to worsen at certain times of the day, it may be related to your body’s circadian rhythm. Understanding these patterns can help guide more effective management strategies. The team at DB Clinic can help assess your symptoms and provide medical guidance tailored to your condition. Schedule your consultation now!

References:

1. Nakao A. Circadian Regulation of the Biology of Allergic Disease: Clock Disruption Can Promote Allergy. Front Immunol. 2020 Jun 12;11:1237.
2. Nakao A. Clockwork allergy: How the circadian clock underpins allergic reactions. J Allergy Clin Immunol. 2018 Oct;142(4):1021-1031.
3. Christ P, Sowa AS, Froy O, Lorentz A. The Circadian Clock Drives Mast Cell Functions in Allergic Reactions. Front Immunol. 2018 Jul 6;9:1526.
4. Nakao A, Nakamura Y, Shibata S. The circadian clock functions as a potent regulator of allergic reaction. Allergy. 2015 May;70(5):467-73.
5. Baumann A, Gonnenwein S, Bischoff SC, Sherman H, Chapnik N, Froy O, Lorentz A. The circadian clock is functional in eosinophils and mast cells. Immunology. 2013 Dec;140(4):465-74.