Exclusive Bee Venom Allergy: Risk Factors and Outcome of Immunotherapy

Introduction: Venom immunotherapy (VIT) is considered to be the gold-standard treatment for patients with Hymenoptera venom allergy. Data regarding VIT in bee venom (BV) allergic patients are scarce. Aim: The aim of this study was to evaluate the outcome of VIT in patients with exclusive BV allergy and to try to define risk factors for VIT-induced systemic reactions (VIT-ISR) and VIT failure. Methods: This is a retrospective study including data from all BV allergic patients that were treated by VIT in the Allergy Unit at the Meir Medical Center in the years 1995-2018. Results: Two hundred and forty-seven patients with exclusive BV allergy were included; 206 (83.4%) preferred to undergo rush buildup. Sixty-nine patients (27.9%) had at least 1 reaction during buildup, with the c-kit mutation being the only significant risk factor (100 vs. 28.9%, p = 0.02). Female gender (25.4 vs. 13.3%, p = 0.04), conventional buildup schedule (26.8 vs. 14.1%, p = 0.04), and c-kit mutation (100 vs. 16.8%, p < 0.01) but not tryptase level were found to be significantly more frequent in recurrent reactors. Females (20.3 vs. 9%, p = 0.03), patients with severe systemic reaction to the index sting (24.3 vs. 9.5%, p = 0.004), and c-kit mutation (66 vs. 12%, p = 0.05) but not tryptase level were found to be risk factors for severe systemic reactions. Conclusion: Despite the considerably high rate of VIT-ISR in patients with exclusive BV allergy, VIT can be performed safely and efficiently. C-kit mutation, and not basal serum tryptase level, seems to be a preferable biomarker for VIT-ISR in these patients.