immunology allergic disorders
Mastocytosis and Mast Cell Activation Syndrome
Key Points
Patients with cutaneous mastocytosis, usually children, typically present with a diffuse salmon or brown, often pruritic maculopapular rash. Systemic mastocytosis causes multifocal bone marrow lesions, usually in adults, but often affects other organs. All types can cause systemic symptoms (most commonly, flushing but sometimes anaphylactoid reactions). For cutaneous mastocytosis, use H1 blockers to relieve symptoms, and in adults, consider treatment with psoralen plus ultraviolet light or topical corticosteroids. For systemic mastocytosis, use H1 and H2 blockers and sometimes cromolyn, and for aggressive mastocytosis, considermidostaurin,avapritinib,interferon alfa-2b, systemic corticosteroids, or splenectomy. For mast cell activation syndrome, target mediators released during activation with antihistamines, leukotriene inhibitors, and mast cell stabilizers. Make sure all patients with mastocytosis carry a prefilled, self-injectingepinephrinesyringe. 