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Your Mast Cell Disease Toolkit

Cut through the confusion of multi-system symptoms with medically vetted resources, trigger-tracking tools, and expert-backed support.

At a Glance: Mast Cell Disease Toolkit

  • Mast cell diseases defined: Mast cell diseases are rare conditions involving mast cells, immune cells that help protect the body. Depending on the condition, mast cells may be abnormal, present in excessive numbers, or become overactive and release chemical mediators when they shouldn’t. 
  • Three major conditions: The mast cell diseases covered in this toolkit include mastocytosis, mast cell activation syndrome (MCAS), and hereditary alpha-tryptasemia (HαT). These conditions are related but are not the same thing. 
  • Anaphylaxis risk: Some people with mast cell diseases are at increased risk for anaphylaxis, a severe and potentially life-threatening allergic reaction. Epinephrine is the first-line treatment for anaphylaxis. People at risk for anaphylaxis should carry it at all times and know when and how to use it.
  • Treatment should be personalized: Treatment depends on the specific mast cell disease, symptoms, and severity. It may include medications that block the effects of mast cell mediators or reduce mast cell activity and, for some forms of mastocytosis, disease-specific therapies.

Mast cell diseases are rare conditions involving mast cells — immune cells that live throughout the body’s tissues and help protect us from infections, allergens, irritants and other threats. When mast cells are abnormal, too numerous or overly reactive, they can release chemical mediators such as histamine and cause symptoms throughout the body. 

There are several mast cell disorders, but three major conditions are mastocytosis, mast cell activation syndrome (MCAS) and hereditary alpha-tryptasemia (HαT). They can cause some similar symptoms, but they have important differences. Mastocytosis involves an abnormal buildup of mast cells. MCAS involves inappropriate or excessive mast cell activation. HαT is a genetic trait associated with elevated alpha-tryptase levels and can increase the risk of certain mast cell-mediated symptoms in some people. 

This Mast Cell Disease Toolkit brings together our medically reviewed information about mast cell disorders. It includes information about diagnosis, symptoms and triggers, treatment, living with the condition, mental health, skin of color, patient stories, podcasts, articles, resources and a glossary of common terms. 

Mast cell diseases happen when mast cells — immune cells found throughout the body’s tissues — become abnormal, build up in excessive numbers or become overactive. The resulting release of chemical mediators can cause symptoms in multiple body organs. 

This introductory page explains how mast cells work. It details common symptoms and triggers, how the major types of mast cell disease differ, and how mast cell diseases are diagnosed and treated.

Read What Are Mast Cell Diseases? →

Mastocytosis is a mast cell disease in which abnormal mast cells build up in tissues or organs. It can affect the skin, bone marrow, digestive system and other parts of the body. Mastocytosis includes different forms, ranging from less severe disease to rare advanced forms. 

Learn about mastocytosis →

MCAS occurs when mast cells become overactive and release chemical mediators too frequently or inappropriately. Symptoms can affect multiple organ systems and may include flushing, rashes, swelling, gastrointestinal symptoms, changes in heart rate or blood pressure and breathing problems. 

Learn about MCAS →

Hereditary alpha-tryptasemia, or HαT, is a genetic trait associated with increased levels of alpha-tryptase, a protein made by mast cells. Not everyone with HαT develops symptoms, but some people with the trait may experience mast cell-mediated symptoms or have an increased risk of severe reactions.

Learn about hereditary alpha-tryptasemia →

Mast cell disease can include skin symptoms — but skin changes may not look the same on all people. Rashes and other skin symptoms can appear differently on darker skin, and some changes may be less noticeable than they are on lighter skin. 

This dedicated resource explains why recognizing mast cell disease in people of color can be challenging and why greater awareness and research are important.

Explore Mast Cell Disease in Skin of Color →

Diagnosis of mast cell disease can be challenging because symptoms can affect many different body systems and overlap with other conditions. The evaluation may include your medical history, a physical examination, blood or urine testing, and, in some cases, a biopsy, imaging, or genetic testing.

Learn how mast cell diseases are diagnosed →

Treatment depends on the type of mast cell disease and the symptoms a person experiences. Medications can help block the effects of mast cell mediators and/or reduce mast cell activation. In addition, people at risk for anaphylaxis due to mast cell disease need an emergency plan that includes immediate access to epinephrine. 

Explore mast cell disease treatment →

Some people with mast cell diseases are at increased risk for anaphylaxis. Anaphylaxis is a medical emergency. Epinephrine is the first-line treatment and should be used promptly when anaphylaxis occurs. People at risk for anaphylaxis due to mast cell disease should keep epinephrine with them wherever they go.

Learn about anaphylaxis and epinephrine →

Living with a mast cell disease can be challenging, particularly when symptoms are unpredictable or triggers are difficult to identify. Symptoms can affect everyday activities, eating, exercise, travel, work, school and social life. 

A personalized treatment plan can help. Many people benefit from tracking symptoms and possible triggers, taking medications as prescribed, preparing for severe reactions and working with healthcare professionals who understand mast cell disorders. 

Get tips for living with mast cell disease →

Living with a chronic condition — especially one that can take time to diagnose and may cause unpredictable symptoms — can affect your emotional well-being. Anxiety, depression, stress and frustration may accompany the physical challenges of mast cell disease. 

Mental health support is an important part of whole-person care. Talk with your healthcare provider if mast cell disease affects your mood, relationships, ability to sleep, or ability to manage everyday life. 

Learn about mental health and mast cell disease →

Mast cell diseases involve many medical terms, including mast cells, mast cell mediators, tryptase, mastocytosis, MCAS, HαT, anaphylaxis and more. 

Our glossary provides plain-language definitions to help patients and families understand the terminology they may encounter during diagnosis and treatment. 

See the Mast Cell Disease Glossary →

Patient Stories

Personal stories can help people understand what it is like to navigate symptoms, diagnosis and treatment. 

Explore stories and conversations about mastocytosis, anaphylaxis, living with systemic mastocytosis and the journey toward a mast cell disease diagnosis. 

Podcasts on Mast Cell Disease

Our mast cell disease podcast series brings together healthcare professionals and people with lived experience to explore the science, diagnosis, treatment and everyday realities of mast cell disorders.

See More Mast Cell Disease Podcasts

Webinars on Mast Cell Disease

Get the latest mast cell disease news, expert Q&As, treatment updates and educational content. Topics range from new and emerging treatments to diagnosis, symptoms, anaphylaxis and living with mast cell disease. 

Mast Cell Disease Glossary 

Mast cell diseases involve many medical terms, including mast cells, mast cell mediators, tryptase, mastocytosis, MCAS, HαT, anaphylaxis and more. 

Our glossary provides plain-language definitions to help patients and families understand the terminology they may encounter during diagnosis and treatment. 

See the Mast Cell Disease Glossary →

Conditions that Can Look Like Mast Cell Disease 

Mast cell disease symptoms can overlap with many other conditions, including allergic reactions, chronic hives, gastrointestinal disorders, cardiovascular symptoms and other inflammatory or immune-related conditions. Having symptoms that resemble mast cell activation does not necessarily mean someone has a mast cell disease. 

Because diagnosis can be complex, people with persistent, unexplained or multi-system symptoms should discuss their concerns with a qualified healthcare professional. 

Learn more about mast cell disease diagnosis →

Mast Cell Disease Resources

These resources can help you prepare for appointments, plan for emergencies, and connect with others who understand life with mast cell disease. 

New to mast cell disease? Start here →

A new diagnosis can bring many questions. You do not need to learn everything at once. The Mast Cell Disease Society (TMS) offers information about mast cell diseases, testing, treatment, and life after diagnosis. 

Visit The Mast Cell Disease Society and choose “New Patients – Start Here” to begin. 

Find a doctor familiar with mast cell diseases 

Finding a healthcare professional who understands your condition can help you take the next step in your care. TMS offers a Find an HCP Resource to help you explore care options. 

Before scheduling, ask whether the doctor treats your specific condition, sees patients in your age group, and requires a referral. You can also check whether the office accepts your insurance. 

Track symptoms and prepare for appointments 

A symptom record can help you explain what happens between doctor visits. TMS offers a symptom tracker and patient guides to help you record symptoms, possible triggers, medicines, and reactions. 

Bring your notes, medicine list, and questions to your appointment. You may want to ask: 

  • What do my test results mean? 
  • What should I do when my symptoms get worse? 
  • How will we know whether my treatment is working? 
  • Which symptoms need emergency care? 

Use this MCD Glossary to look up unfamiliar words. Ask your healthcare team to explain how each term relates to your care. 

Prepare for emergency care 

Planning ahead can make it easier to share important information during an emergency. TMS provides an Emergency Alert Card and an Emergency Room Response Plan through its patient resources page. 

Review these materials with your doctor. Ask your doctor to help create a plan specific to your needs, including when to use prescribed emergency medicine and when to seek emergency help. Share your plan with family members and others who may help during a reaction. 

Connect with others who understand MCD 

Living with mast cell disease can feel isolating. Talking with people who have similar experiences may help you feel understood and give you a place to share everyday concerns. 

TMS offers virtual support groups and online communities. Visit TMS’s Find Support page to explore ways to connect. 

Find information for everyday life about Mast Cell Disease 

You may have questions about daily routines, relationships, or the emotional effects of living with a long-term condition. These Allergy & Asthma Network guides offer more information: 

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