HYMENOPTERA STING ANAPHYLAXIS AND URTICARIA PIGMENTOSA - CLINICAL FINDINGS AND RESULTS OF VENOM IMMUNOTHERAPY IN 10 PATIENTS

Background: Occasional patients with urticaria pigmentosa and anaphyla xis after Hymenoptera stings have been described. In this situation th e question arises: Is anaphylaxis IgE-mediated or induced by pharmacol ogic mediator release from mast cells? Methods: We investigated 10 pat ients with histologically confirmed urticaria pigmentosa and a history of anaphylaxis after honeybee or Vespula stings before and during imm unotherapy with the respective venom. Results: In eight of 10 patients , an elevated serum tryptase level was found. In two of 10 patients, n o venom-specific IgE could be detected by either skin tests or RAST. F ive patients had no detectable venom-specific serum IgE, and in the re maining patients the level was low (<1 Phadebas RAST unit). Venom immu notherapy was well tolerated and caused only one mild systemic reactio n in a patient during the dose increase phase. Six patients were re-st ung while receiving venom immunotherapy: only one had a mild systemic reaction (angioedema:) after a Vespula sting. Conclusion: Anaphylactic symptoms after Hymenoptera stings in patients with urticaria pigmento sa are most often IgE-mediated but can occasionally be observed in the absence of IgE sensitization to venom allergens. Venom immunotherapy can be safely and successfully used in patients with urticaria pigment osa and sting anaphylaxis.