Image: Hope for sufferers

What is Mast Cell Activation Syndrome?

Mast Cell Activation Syndrome (MCAS) is a condition which can develop in children or adults. MCAS forms part of a spectrum of mast cell disorders. People with MCAS may also have other mast cell disorders such as mastocytosis or hereditary alpha tryptasemia syndrome (HATS).

In people affected by MCAS, chemicals called mast cell mediators are released too frequently or abundantly, and/or in response to triggers that are not typically considered to be harmful, for example; foods or chemicals in the environment. This can lead to which causes a wide range of symptoms that affect multiple parts of the body.Triggers and symptoms of MCAS vary greatly between individuals. Triggers can include fragrances, exercise, stress and changes in temperature. MCAS symptoms can come and go and may often change over time within the same person. This can make it difficult to identify specific triggers, and the number of triggers and severity of symptoms may continue to increase as the condition progresses.

More research is needed to understand MCAS. Sometimes the condition occurs in family groups, suggesting that there may be genetic causes of MCAS. For example, HATS is a genetic condition caused by the presence of extra copies of the alpha tryptase gene (TPSAB1). Since the genetic causes of mastocytosis and HATS are well-characterised, genetic tests for these conditions are available.

Further information about mast cell disorders including Mastocytosis and MCAS can be found on Patient Info.

Anaphylaxis in MCAS

People who have MCAS are at an increased risk of having an Anaphylactic reaction after encountering a trigger. Anaphylaxis is a potentially life-threatening allergic reaction, it has a rapid onset of symptoms and it is important to be aware of the ABC signs:

Airways: look for a persistent cough, swollen tongue or lips, and difficulty swallowing. 

Breathing: look for difficulty breathing and wheezing. 

Circulation/Consciousness: look for reduced blood pressure, confusion, and collapsing. 

Pre-loaded adrenaline auto-injectors, commonly known as EpiPens, are prescribed to combat anaphylaxis. If you are at risk of anaphylaxis you need to carry your auto-injector at all times, and give an injection as soon as any symptoms of anaphylaxis occur. Always call an ambulance immediately following injection, even if there is a drastic improvement. 


People who have MCAS often have at least one additional condition.

Common comorbidities include connective tissue disorders such as Ehlers Danlos Syndrome (EDS) and Marfansdysautonomia, such as postural orthostatic tachycardia syndrome (POTS), and type 2 diabetes.

The relationship between MCAS and many of these comorbidities is yet to be fully understood, and more research is required.

Further information on comorbidities can be found in the Royal College of GPs Ehlers Danlos Syndromes Toolkit. 

Can you Move 4 Mast Cell?

The MCAS community is coming together to take action! Together, we can fight mast cell disease. Plan your event for September 2022, Move 4 Mast Cell and join the fight today!

Imagine a world where people with Mast Cell Activation Syndrome (MCAS) are understood, diagnosed swiftly and have access to effective treatment.

MCAS is a life-destroyer. It presents with malicious and miserable symptoms, raging through the body and wreaking havoc. It can change its presentation mysteriously and regularly evades effective medical systems or diagnosis. Splitting the medical community whilst leaving those affected in limbo, it halts normal life in its tracks, leaving exhaustion, severe allergies, discomfort and pain in its wake. And in some cases can even lead to life-threatening anaphylaxis. 

At present there is no cure for MCAS. So, not only can it be a fight to achieve an effective diagnosis, but thereafter it is a struggle to learn to live with the disease and sadly for many it can take years, but most commonly decades before they are able to manage their conditions and for a select few, obtain a much sought-after diagnosis. It is a question of self-management combined with medical treatment.

Mast Cell Action is setting out to tackle the disease on multiple levels; providing support, raising awareness and funding quality research to improve outcomes and the quality of life for people affected.

We believe that everyone affected by MCAS deserves to have their symptoms acknowledged and experiences listened to, to achieve a correct diagnosis and to receive the medical care and support that they need.

We are the only UK charity providing support, information and guidance specifically and exclusively to the MCAS community and health professionals.

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Charity founder, Gawain Paling says; People with mast cell activation syndrome are caught in a diagnostic Odyssey for years. They bounce around the system seeing one specialist after another - often for decades - until they find one doctor that is prepared to join the dots and take them seriously. It's just not good enough.

Sign up today to 'Move 4 Mast Cell' - run a marathon, do a skydive, take a coastal walk - or choose your own movement to help us fight MCAS.

MCAS can limit many things in life, but your love gives us all vital hope for a brighter tomorrow. Thank you for being there for our community.

Find out more and sign up here.

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