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Mast cell Activation Syndrome

Allergy, Digestion | April 10, 2018 | Author: Naturopath

allergy, Digestion

Mast cell Activation Syndrome

With a prevalence as high as 5-10% of the population—surely mast cell activation syndrome is something you would have heard of. However, this syndrome is poorly understood and under-recognised by health professionals. Patients with mast cell activation syndrome or MCAS for short have an endless list of triggers which can result in allergic symptoms, digestive problems and psychiatric conditions.

What are mast cells?

These are specialised immune cells that form part of the body’s defence system. They reside in all body tissues ready to react to injury or foreign bodies by releasing chemical mediators such as histamine and leukotrienes. In a healthy person these reactions are beneficial to provide protection and promote wound healing.

When mast cells go wrong

When mast cells go wrongIn a person with MCAS, the chemicals released by mast cells are inappropriately triggered by a variety of stimuli including food, exercise, stress, temperature changes and chemicals.

This causes a negative effect on the body leading to allergic and inflammatory diseases affecting different areas of the body.

For some sufferers identifying what triggers the condition can be obvious but many struggle to find what is the cause of their symptoms.


Mastocytosis is a disorder that results in an excessive number of mast cells in your body. It is a rare but well-known mast cell disorder which is currently easier to diagnose than MCAS. The difference between these two conditions is that in MCAS there is little or no increase in the number of mast cells. What they do have in common is excessive sensitivity of mast cells.

Symptoms of mast cell activation syndrome

The onset of MCAS is often sudden, affecting both adults and children. The symptoms can mimic many other conditions and present with such a wide-range of unpleasant issues which often baffles the physician and patient.

MCAS is a multi-system condition which can involve the following conditions and symptoms including:

When mast cells go wrongDermatological—rash’s and skin legions, itchy skin, eczema, hives, flushing

Musculoskeletal—chronic pain, fibromyalgia

Neurologic and psychiatric symptoms—headaches/migraines, restless legs syndrome, sleep disorders, tinnitus, pain hypersensitivity, mood and psychiatric disorders, fatigue

Respiratory—rhinitis, sinusitis, dyspnoea, sleep apnoea, ulcers, post-nasal drip

Immunologic—food intolerances/allergies, autoimmunity

Gastrointestinal—bloating, flatulence, pain, nausea, vomiting, bowel irregularities, malabsorption

Endocrine/metabolic—painful periods, endometriosis, underactive or overactive thyroid, elevated fats or cholesterol in the blood, weight gain

Genitourinary—cystitis, erectile dysfunction, low libido

MCAS can present simultaneously in patients who have Ehlers Danlos Syndrome (EDS) a connective tissue disorder, and/or Postural Orthostatic Tachycardia Syndrome (POTS).

Diagnosing MCAS

To be diagnosed with mast cell activation syndrome a person must fit the following criteria:

  • symptoms must be related to mast cell mediator release
  • affects more than two organ symptoms i.e. the skin, digestion and respiratory system
  • a decrease in severity or frequency or complete resolution of symptoms if antihistamines, antileukotrienes or mast cell stabilising medications are taken
  • must be evidence of an increase in urine or blood marker of mast cell activation i.e. elevated histamine or PGD2 or it’s metabolite
  • primary and secondary causes of mast cell activation have been ruled out

How to reduce MCAS

There are many different treatment considerations, depending on the person’s symptoms. Overall, identifying and avoiding triggers is the main treatment objective followed by an increase in tolerance.


How to reduce MCASCertain foods can stimulate mast cell activation and contribute to the release of histamine.

This includes common food allergens such as tree nuts, soy, corn, wheat, dairy and seafood.

It could also be foods which contain histamine or block the body from being able to break it down via an enzyme called DAO.

A low histamine diet might be worthwhile trying to reduce histamine load and to identify trigger foods.

As part of this diet refraining from alcohol is a must as it inhibits DAO and causes mast cell activation.
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Anti-allergy nutrients such as quercetin, perilla and albizzia can assist the body in reducing the allergic response. The enzyme DAO requires vitamin B6, zinc and vitamin C which assist in the breakdown of histamine. Nutrients such as fish oil and turmeric which are natural anti-inflammatories may be useful here too.

Improve digestive function

If there is poor digestive health this will have a negative impact on mast cells. Ensuring there are adequate levels of beneficial bacteria will help to inhibit mast cell degranulation and dysbiosis. Make sure the diet contains adequate fibre and for some people a detoxification program may be necessary.
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Reduce stress

Having high levels of stress can have a detrimental effect on mast cells. As part of the stress response corticotropin-releasing hormone (CRH) is secreted by the hypothalamus in the brain and leads to mast cell activation in sensitive individuals. Ways to decrease stress includes regular exercise (avoid excess body heat if it is a trigger), breathing exercises and finding a better work-life balance. Magnesium, passionflower, zizyphus, withania, kava and magnolia are all examples of supplements to reduce the stress response and promote a good night’s sleep.
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MelatoninIf there are other hormonal imbalances such as low levels of melatonin this can lead to mast cell degranulation and the secretion of chemical mediators. Melatonin is what makes us feel sleepy at night and low levels can occur due to jet lag, shift work, alcohol, caffeine, stress, exposure to light at night (especially blue light), blood sugar imbalances and age.

Ways to boost melatonin include having a cut of time for screens way before bedtime, exposure to sunlight in the morning, avoiding alcohol and caffeine and having a good sleep routine.
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MCAS at a glance

  • a syndrome which involves multiple systems in the body
  • occurring when mast cells are sensitive and easily activated due to a variety of triggers in the diet and environment
  • treatment involves identifying and avoiding triggers as well as increasing tolerance  Australia’s best online discount chemist


Frieri M, et al. Mast cell activation syndrome: a review. Curr Allergy Asthma Rep. 2013 Feb;13(1):27-32

Afrin LB, et al. Mast cell activation disease: An underappreciated cause of neurologic and psychiatric symptoms and diseases. Brain Behav Immun. 2015 Nov;50:314-321

Mondovi B, et al. Effects of amine oxidases in allergic and histamine-mediated conditions. Recent Pat Inflamm Allergy Drug Discov. 2013 Jan 1;7(1):20-34

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