immunology allergic disorders
Mastocytosis and Mast Cell Activation Syndrome
Introduction
Mastocytosisis mast cell proliferation with infiltration of skin or other tissues and organs.Mast cell activation syndromeis increased and inappropriate activation of mast cells without clonal proliferation. Symptoms result mainly from mediator release and include pruritus, flushing, and dyspepsia due to gastric hypersecretion. Diagnosis is by skin or bone marrow biopsy or both. Treatment is with antihistamines and control of any underlying disorder. (See also Overview of Allergic and Atopic Disorders .) Mastocytosis is a group of disorders characterized by proliferation of mast cells and infiltration of the skin, other organs, or both. Pathology results mainly from release of mast cell mediators, including histamine,heparin, leukotrienes, and various inflammatory cytokines. Histamine causes many symptoms, including gastric symptoms, but other mediators also contribute. Significant organ infiltration may cause organ dysfunction. Mediator release may be triggered by physical touch, exercise, alcohol, nonsteroidal anti-inflammatory drugs (NSAIDs), opioids, insect stings, or foods. Etiology in many cases of mastocytosis involves an activating mutation (D816V) in the gene coding for the stem cell factor receptor c-kit, which is present on mast cells. The result is autophosphorylation of the receptor, which causes uncontrolled mast cell proliferation. 