Hymenoptera Anaphylaxis as a Clonal Mast Cell Disorder.

Up to 7% of adult patients with Hymenoptera venom allergy may suffer from a clonal mast cell disease. Patients with clonal mast cell disease and Hymenoptera venom anaphylaxis are commonly males, without skin lesions, and anaphylaxis is characterized by hypotension and syncope in the absence of urticaria and angioedema. A normal value of tryptase does not exclude a mastocytosis. The diagnosis of a mast cell disease leads to several therapeutic consequences concerning the treatment of Hymenoptera venom allergy as matter of fact these patients have to undergo long-life venom immunotherapy, to prevent further, potentially fatal severe reactions.