Safety of a two-day ultrarush insect venom immunotherapy protocol in comparison with protocols of longer duration and involving a larger number of injections.

Abstract

Insect venom immunotherapy (VIT) is initiated by a dose increase protocol administered usually over 7 to 9 days. Shorter protocols have the advantage of reducing the patient's stay in the hospital. Very few data are currently available on the safety of shorter VIT dose increase protocols. The aim of this study was to investigate whether a reduction in the duration of the VIT dose increase protocol from 7 to 9 days to 2 days causes an increase in the incidence and severity of adverse reactions. Between 1992 and 1997 we administered VIT to 1055 patients allergic to bee or wasp venom. We shortened the 7- to 9-day rush protocol stepwise to 2 days by reducing the number of injections and increasing the initial dose and compared the incidence and severity of adverse reactions. The patients were retrospectively divided into 3 cohorts: 20 injections over 7 to 9 days (cohort 1, 317 patients), 10 to 14 injections over 3 to 6 days (cohort 2, 335 patients), and 9 injections over 2 days (cohort 3, 403 patients). We observed no severe adverse reactions in any of the cohorts during VIT. Adverse reactions were treated in 7.1% of the patients by oral and in 2.9% by intravenous antihistamines and in 0.8% by systemic corticosteroids. The incidence of adverse reactions declined significantly from 22.4% in cohort 1 to 13.7% in cohort 2 and 10.7% in cohort 3 with reduced number of injections (P <.001). The incidence and severity of adverse reactions decline if the VIT dose increase protocol is shortened to 2 days.