Mastocytosis is a disorder that may occur in both children and adults. It is caused by the presence of too many mast cells in your body. You can find mast cells in skin, lymph nodes, internal organs (such as the liver and spleen) and the linings of the lung, stomach, and intestine. Mast cells play an important role in helping your immune system defend these tissues from disease.
The presence of too many mast cells, or mastocytosis, can occur in two forms—cutaneous and systemic. The most common cutaneous (skin) form is also called urticaria pigmentosa, which occurs when mast cells infiltrate the skin. Systemic mastocytosis is caused by mast cells accumulating in the tissues and can affect organs such as the liver, spleen, bone marrow, and small intestine. Researchers first described urticaria pigmentosa in 1869. Systemic mastocytosis was first reported in the scientific literature in 1949. The true number of cases of either type of mastocytosis remains unknown, but mastocytosis generally is considered to be an “orphan disease.” (Orphan diseases affect approximately 200,000 or fewer people in the United States.) When too many mast cells are in your body, the additional chemicals can cause:
Your healthcare provider can diagnose cutaneous mastocytosis by the appearance of your skin and confirm it by finding an abnormally high number of mast cells on a skin biopsy. Your provider can diagnose systemic mastocytosis by finding an increased number of abnormal mast cells during an examination of your bone marrow.
Other tests that are important in evaluating a suspected case of mastocytosis include:
1. Measurement of a protein (tryptase) from mast cells in your blood
2. A search for specific genetic mutations that health experts associate with this disease
Healthcare providers use several medicines to treat mastocytosis symptoms, including antihistamines (to prevent the effect of mast cell histamine–a chemical) and anticholinergics (to relieve intestinal cramping). A number of medicines treat specific symptoms of mastocytosis. Certain antihistamines work specifically against ulcers; proton pump inhibitors also relieve ulcer-like symptoms. Epinephrine treats symptom flares which occur with shock (anaphylaxis).
Two types of antihistamines can be used to prevent itching, flushing and low blood pressure.
1. Steroids treat malabsorption, or impaired ability to take in nutrients.
2. Cromolyn sodium may help reduce cramping in the abdomen.
In the very rare cases in which mastocytosis is malignant, cancerous, or associated with a blood disorder, steroids and/or chemotherapy may be necessary.
Further information may be obtained at the Mastocytosis Society website www.tmsforacure.org.