Systemic mastocytosis (mas-to-sy-TOE-sis) is a rare disorder that results in too many mast cells building up in your body. A mast cell is a type of white blood cell. Mast cells are found in connective tissues throughout your body. Mast cells help your immune system function properly and normally help protect you from disease.
When you have systemic mastocytosis, excess mast cells build up in your skin, bone marrow, digestive tract or other body organs. When triggered, these mast cells release substances that can cause signs and symptoms similar to those of an allergic reaction and, sometimes, severe inflammation that may result in organ damage. Common triggers include alcohol, spicy foods, insect stings and certain medications.
Products & Services
Signs and symptoms of systemic mastocytosis depend on the part of the body affected by excessive mast cells. Too many mast cells can build up in the skin, liver, spleen, bone marrow or intestines. Less commonly, other organs such as the brain, heart or lungs also may be affected.
Signs and symptoms of systemic mastocytosis may include:
- Flushing, itching or hives
- Abdominal pain, diarrhea, nausea or vomiting
- Anemia or bleeding disorders
- Bone and muscle pain
- Enlarged liver, spleen or lymph nodes
- Depression, mood changes or problems concentrating
The mast cells are triggered to produce substances that cause inflammation and symptoms. People have different triggers, but the most common ones include:
- Skin irritation
- Spicy foods
- Insect stings
- Certain medications
When to see a doctor
Talk to your doctor if you have problems with flushing or hives, or if you have concerns about the signs or symptoms listed above.
Most cases of systemic mastocytosis are caused by a random change (mutation) in the KIT gene. Typically this flaw in the KIT gene is not inherited. Too many mast cells are produced and build up in tissues and body organs, releasing substances such as histamine, leukotrienes and cytokines that cause inflammation and symptoms.
Complications of systemic mastocytosis can include:
- Anaphylactic reaction. This severe allergic reaction includes signs and symptoms such as rapid heartbeat, fainting, loss of consciousness and shock. If you have a severe allergic reaction, you may need an injection of epinephrine.
- Blood disorders. These can include anemia and poor blood clotting.
- Peptic ulcer disease. Chronic stomach irritation can lead to ulcers and bleeding in your digestive tract.
- Reduced bone density. Because systemic mastocytosis can affect your bones and bone marrow, you may be at risk of bone problems, such as osteoporosis.
- Organ failure. A buildup of mast cells in body organs can cause inflammation and damage to the organ.
Systemic mastocytosis care at Mayo Clinic
Nov. 20, 2020
- Systemic mastocytosis. Genetic and Rare Diseases Information Center. https://rarediseases.info.nih.gov/diseases/8616/systemic-mastocytosis. Accessed Oct. 8, 2020.
- Mastocytosis. Merck Manual Professional Version. https://www.merckmanuals.com/professional/immunology-allergic-disorders/allergic,-autoimmune,-and-other-hypersensitivity-disorders/mastocytosis. Accessed Oct. 8, 2020.
- Valent P, et al. Mastocytosis: 2016 updated WHO classification and novel emerging treatment concepts. Blood. 2017; doi:10.1182/blood2016-09-731893.
- Shomali W, et al. The new tool "KIT" in advanced systemic mastocytosis. Hematology. 2018; doi:10.1182/asheducation-2018.1.127.
- Fletcher L, et al. Novel approaches for systemic mastocytosis. Current Opinion in Hematology. 2019; doi:10.1097/MOH.0000000000000486.
- Coltoff A, et al. Relevant updates in systemic mastocytosis. Leukemia Research. 2019; doi:10.1016/j.leukres.2019.04.001.
- AskMayoExpert. Systemic mastocytosis. Mayo Clinic; 2019.
- Scherber RM, et al. How we diagnose and treat systemic mastocytosis in adults. British Journal of Haematology. 2018; doi:10.1111/bjh.14967.
- Pardanani A. Systemic mastocytosis in adults: 2019 update on diagnosis, risk stratification and management. American Journal of Hematology. 2019; doi:10.1002/AJH.25371.
- Li JTC (expert opinion). Mayo Clinic. Oct. 14, 2020.
Products & Services