Effectiveness of Venom Immunotherapy: A Single-center Experience

INTRODUCTION: Treatment outcomes in patients who completed or suddenly discontinued venom immunotherapy (VIT) are still uncertain.
METHODS: A total of 71 patients who received conventional VIT were included in the study. Patients who experienced field stings were invited to the clinic, and allergic reactions were evaluated.
RESULTS: The median age of the patients was 43 (35–54) years, and 70.4% (n = 50) were male. Of the patients, 32 (45.1%), 29 (40.8%), and 10 (14.1%) received VIT with Vespula venom, Apis venom, and both venoms, respectively. Treatment was interrupted in 57 (80.2%) patients who could not access VIT due to drug unavailability. Thirty-eight (53.5%) patients experienced re-sting after initiation of VIT. Of the re-stung patients, 22 (57.8%) developed local reactions (LRs), and 16 (42.1%) developed systemic allergic reactions (SARs). All four patients who experienced anaphylaxis after re-sting were those whose treatment was incomplete of VIT. The VIT duration of patients with SARs was shorter than those with LRs, although not significantly. SAR after the sting was significantly lower in patients with VIT duration > 4 years. Thirty-three (46.5%) patients reported carrying AAI, and 8 of them self-administered adrenaline auto-injector (AAI).
DISCUSSION AND CONCLUSION: The effectiveness of VIT was correlated with its duration, and VIT lasting at least four years prevents SARs after field stings. The proportion of AAI carriers and the rate of self-administration were low among patients on VIT.