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Living with Systemic mast cell disease

A blood condition (systemic mastocytosis) in which mast cells build up and cause tiredness, flushing, belly problems, and allergic reactions.

Understanding Systemic mast cell disease

Systemic mastocytosis is a blood condition that can affect many body systems.

Signs can appear at any age but usually appear after the teen years. Symptoms often include tiredness, flushing, belly pain, and breathing or blood pressure changes. Many people get raised brown skin patches that sting or itch. Nearly half have severe allergic reactions (anaphylaxis). There are five subtypes, from mild (indolent and smoldering) to severe types.

Signs & symptoms

Symptoms vary from person to person. GARD lists these:

  • Extreme tiredness
  • Skin flushing and warmth
  • Nausea, belly pain, bloating, or diarrhea
  • Nasal congestion and shortness of breath
  • Low blood pressure and lightheadedness
  • Raised, itchy brown skin patches

Not everyone has every symptom. GARD's list comes from the Human Phenotype Ontology.

Diagnosis

  1. Talk with your doctor

    Share the symptoms you've noticed, when they started and your family health history. Notes and photos can help.

  2. See a specialist

    Specialists who may be involved include blood and bone marrow specialists and cancer specialists.

  3. Ask which tests can help

    Your care team will decide which exams and tests can confirm the diagnosis.

  4. Connect with expert centers

    The Mast Cell Disease Society may keep lists of experts for this condition.

Care & treatment

Care team
Blood and bone marrow specialists (hematologists); Cancer specialists (oncologists)
Expert care
Expert lists: The Mast Cell Disease Society
Treatment
GARD doesn't list specific treatments for this condition. Your care team will tailor care to your symptoms.
Research
Clinical trials and observational studies may be options. See the research section below.

General information, not medical advice. Your care team makes the decisions.

Everyday life

Living with a rare condition is easier with support.

  • Connect with The Mast Cell Disease Society and other patient organizations
  • Keep notes on symptoms, changes and questions for appointments
  • Ask about patient registries that help research
  • Look into financial aid and travel resources for care visits
Bring these questions to your next doctor visit
Which subtype do I have?
What should I do if I have signs of a severe allergic reaction?
Which triggers should I avoid?

Quick facts

Symptoms usually startany time in life

GARD doesn't describe a cause for this condition yet.

Blood

Also known as: smcd - systemic mast cell disease; systemic mastocytosis; systemic tissue mast cell disease

Patient organizations

Source: NIH GARD · Systemic mast cell diseaseGARD ID 8616 · GARD page updated September 2026 · Plain-language summary by Know Rare; editorial review pending. General information, not medical advice.

You are more than your diagnosis

Perspectives from people navigating life with Systemic mast cell disease.

Explore the Systemic mast cell disease blog

Explore research for Systemic mast cell disease

Explore actively recruiting Systemic mast cell disease studies with HealthSpark.

HealthSpark

Find actively recruiting studies for Systemic mast cell disease with HealthSpark. Share your city to explore research near you.

  • Recruiting studies from ClinicalTrials.gov
  • Share your city to look for research near you
  • Eligibility is confirmed by the study team

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Powered by HealthSpark, our AI chat helper · Study information from ClinicalTrials.gov · Eligibility is confirmed by the study team.

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