Clinical course and reaction profile of patients undergoing venom immunotherapy

Abstract

Aim: Bee venom allergy is a major cause of anaphylaxis in adults. Venom Immunotherapy (VIT) is the only proven curative treatment, but the frequency and management of local and systemic reactions during therapy are essential considerations for safety. This study aimed to evaluate the demographic and clinical characteristics of patients undergoing VIT and to analyze reaction rates and management strategies.

Materials and Methods: This retrospective single-center study included 31 patients (18 honeybee, 13 vespid)who received VIT at the Ankara Bilkent City Hospital Allergy and Clinical Immunology Clinic between October 2024 and September 2025. All patients received a standard premedication protocol. Demographic, clinical, and laboratory data were obtained from medical records. Systemic reactions were classified according to the Ring–Messmer grading system, and management strategies for VIT-related reactions were analyzed.

Results: The mean age of the patients was 41.5 ± 15.3 years, and 61.3% were male. A history of beekeeping was significantly more common among honeybee-allergic patients (p = 0.009). Index sting reactions were often; Grade 3 reactions were observed in 58.1% of cases. Respiratory (77.4%) and cardiovascular (64.5%) involvement were the most common clinical manifestations; adrenaline was administered in 54.8% of index reactions. During VIT, 12 patients (38.7%) developed reactions, of which 7 (22.6%) were systemic. Systemic reactions occurred more frequently in the honeybee VIT group than in the vespid group, although this difference was not statistically significant (p = 0.101). Most systemic reactions were mild to moderate and occurred early during treatment. In selected cases, VIT was successfully continued with dose adjustment and adjunctive omalizumab therapy.

Conclusion: Systemic reactions during VIT were more frequent among honeybee venom–allergic patients but were generally mild to moderate and manageable. With close monitoring, appropriate dose modifications, and biologic support when indicated, VIT can be safely continued in most patients.