About Systemic Mastocytosis
Systemic Mastocytosis results from clonal proliferation of mast cells due to activating mutations, most commonly KIT D816V, leading to accumulation of abnormal mast cells in bone marrow, lymphoid tissues, skin, and other organs. Mast cells produce numerous mediators including histamine, tryptase, heparin, and various cytokines that cause symptoms upon release.
The disease is classified into several subtypes: indolent systemic mastocytosis (ISM), smoldering systemic mastocytosis (SSM), systemic mastocytosis with associated hematologic neoplasm (SM-AHN), aggressive systemic mastocytosis (ASM), and mast cell leukemia (MCL), with widely varying prognosis and management. Symptoms result from both mast cell accumulation and mediator release.
Mediator-related symptoms include flushing, pruritus (itching), abdominal symptoms, and anaphylaxis. Mast cell accumulation contributes to bone marrow dysfunction with cytopenias, osteoporosis, organomegaly, and tissue infiltration. Risk factors for mediator release include food additives, medications, insect stings, stress, and heat. Many patients develop myelodysplastic syndrome or acute myeloid leukemia as a complication.
Common Symptoms of Systemic Mastocytosis
Recognizing the signs of Systemic Mastocytosis early can lead to faster diagnosis and better outcomes. Symptoms may vary in severity from person to person. If you or a loved one are experiencing any of the following, consider speaking with a specialist.
- Flushing and itching, especially with triggers like heat or food
- Abdominal pain, diarrhea, and malabsorption
- Bone pain and osteoporosis
- Anaphylactic reactions with throat tightness and hypotension
- Headaches and cognitive difficulties
- Hepatomegaly and splenomegaly
Who Systemic Mastocytosis Affects
Systemic Mastocytosis can present at any age, from childhood to elderly, though adult onset is most common. It affects males and females roughly equally. The disease occurs across all racial and ethnic groups.
The KIT D816V mutation, present in approximately 90% of adult cases, is typically somatically acquired and not inherited. Some pediatric cases with different KIT mutations or other genetic alterations have different clinical courses.
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Help Paying for Systemic Mastocytosis Treatment
Charity funds and drugmaker programs for Systemic Mastocytosis, checked at the source. Pick your insurance to see what fits.
- From a charity · Blood Cancer United (formerly The Leukemia & Lymphoma Society)Acute Myeloid Leukemia Co-Pay Fund (covered diagnoses include Mastocytosis) fundOpen
Pays for: Insurance premiums and treatment-related copays, deductibles and coinsurance, up to $4,000 per year. Requires health insurance (any kind).
Side Effect Explorer
Real-world side effect reports from the FDA Adverse Event Reporting System (FAERS). Includes both FDA-approved drugs and investigational therapies from active clinical trials. Click any drug to see what patients reported.
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Genetic Testing
Genetic testing can confirm a diagnosis, guide treatment decisions, and identify family members who may be at risk.
The KIT gene page lists every condition Orphanet links to the gene and the open trials that name it.
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Trusted Systemic Mastocytosis Resources
Reputable organizations and medical references for learning more about Systemic Mastocytosis, including disease registries, foundation resources, and clinical guidelines.