Venom Immunotherapy in Clinical Practice: A Retrospective Real-World Cohort

Venom immunotherapy (VIT) is the only disease-modifying treatment for Hymenoptera venom allergy, but real-world data describing VIT-related reactions and individualized premedication practices remain limited. We retrospectively evaluated 16 adults undergoing VIT with a target maintenance dose of 100 µg administered every 4 weeks at a tertiary allergy center between January 2024 and December 2025, focusing on clinical characteristics, premedication, treatment-related reactions, and field-sting outcomes during follow-up of up to 24 months. All patients had severe index reactions (Müller grade III-IV); 13 (81.3%) received Vespula VIT and 3 (18.8%) honey bee VIT. Premedication was initiated before VIT in seven patients (43.8%), including omalizumab in five (31.3%). During the 7-week up-dosing phase, five patients (31.3%) developed local reactions, whereas no systemic reactions occurred (0/16; 95% CI: 0-20.6%). During maintenance, one systemic reaction occurred (6.3%), requiring adrenaline and one-night intensive care admission, after which VIT was discontinued. Two patients were re-stung during follow-up and developed only local reactions. In this small, selected real-world cohort, no systemic reactions were observed during the up-dosing phase, whereas one systemic reaction occurred during maintenance. Given the limited sample size, wide confidence intervals, and frequent use of individualized premedication, these findings should be interpreted as descriptive observations and not as evidence establishing the safety of VIT or the effectiveness of premedication.