Venom immunotherapy in clinical practice: comparison of two ultra-rush protocols.

Summary: Background. Ultra-rush venom immunotherapy protocols have shown to be a safe and effective approach to prevent the occurrence of systemic reactions after hymenoptera stings. The aim was to describe our experience with two ultra-rush protocols - a five-step with 1 µg starting dose and a six-step with 0.1 µg starting dose, as well as to compare their safety profile. Methods. This is a retrospective study of all the patients who underwent VIT with honey bee or wasp venom between January 2008 and December 2021, in our department. Results. A total of 110 patients was included, with 109 patients (99%) completing the protocol. A total of 63 (57%) patients had no local or systemic reactions. Most systemic reactions occurred with 20 µg or higher doses (24, 83%). There were no documented grade IV systemic reactions (Mueller grading). No differences were found in local or systemic reactions regarding sex, atopy, β-blocker medication, the severity of the index reaction, ID test positivity, levels of total IgE, specific IgE and tryptase (all p > 0.05). Younger age, treatment with bee VIT or being a beekeeper were associated with more systemic reactions (p = 0.035, 0.006 and 0.047, respectively). No statistical differences in the number of local and systemic reactions were found when comparing both protocols (p = 1.000). Conclusions. Ultra-rush protocols are safe and effective, but systemic reactions are to be expected, especially with honeybee. Our data supports that ACE inhibitors do not compromise safety. Beginning with 1 µg is safe and can save time and resources.