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

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.