Treatment of Mastocytosis For cutaneous mastocytosis, H1 blockers and possibly psoralen plus ultraviolet light or topical corticosteroids For systemic mastocytosis and mast cell activation syndrome, H1 and H2 blockers, cromolyn, and ketotifen, montelukast, aspirin For aggressive forms, midostaurin, avapritinib, interferon alfa-2b, corticosteroids, or splenectomy Cutaneous mastocytosis H1 blockers are effective for symptoms.