Analysis of the safety and tolerance of three buildup protocols of insect venom immunotherapy frequently used in Spain.

INTRODUCTION: Hymenoptera venom immunotherapy (VIT) is an effective treatment but not one devoid of risk as both local and systemic adverse reactions may occur especially in the initial stages of treatment. We compared the tolerance to three buildup protocols of VIT and analyzed risk factors associated with adverse reactions occurring in this phase.

METHODS: We enrolled 165 patients divided into three groups based on the buildup protocol used (3, 4, 9 weeks). Severity of systemic reactions was evaluated according to World Allergy Organization model. Results were analyzed using exploratory descriptive statistics and variables were compared using analysis of variance.

RESULTS: Fifty-three patients (32%) experienced some form of adverse reaction, 43 were local and 10 systemic. Local reactions were immediate in 27 patients (63%) and delayed in 16 (37%). Severity of local reaction was slight/moderate in 15 patients and severe in 13. Systemic reactions were grade 1-2. No significant association was found between the treatment modality and the appearance of local or systemic adverse reactions or the type of local reaction. We only found a statistically significant association of severity of the local reaction with female gender. As for the risk factors associated with systemic reactions at buildup phase, we found no significant differences in these values depending on protocol used or the insect responsible.

CONCLUSIONS: The buildup protocols compared proved to be safe and did not differ significantly from one another. In the population studied the 9-week schedule presented no systemic reactions, so it can be considered the safest protocol.