LAUSR

Purpose of review Hymenoptera-induced allergy (HVA) is a common cause of anaphylaxis and may be fatal. It is associated with systemic mastocytosis in about 7% of adult patients. Systemic mastocytosis is a proliferative disorder of hematopoietic mast cell progenitors. There is recent data on the association between systemic mastocytosis and HVA. Recent findings Hymenoptera venoms are the most common immunoglobulin E-mediated elicitors of anaphylaxis in patients with mastocytosis. Some patients with systemic mastocytosis do not have cutaneous involvement and have only been identified because of HVA. These patients do have distinct demographic, clinical, and laboratory features as compared with patients with mastocytosis with skin lesions. They show a male predominance, more severe (cardiovascular) as compared to skin symptoms, lower baseline serum tryptase, less bone marrow mast cell aggregates, and KIT mutations restricted to mast cell lineage. Summary Although hymenoptera-induced anaphylaxis is not primarily a mast cell-driven hematological disorder, the latter is present in a significant proportion of patients and has to be excluded by basal serum tryptase determination, skin inspection as well as exclusion of systemic mastocytosis by D816V mutation analysis in peripheral blood and/or bone marrow examination in selected patients.