Worm M, et al. - Researchers intended to identify and prioritize factors related to an increased risk of developing severe anaphylaxis, by using data from the Anaphylaxis Registry (122 centers in 11 European countries) and logistic regression models. Endogenous and exogenous factors, that were found to be associated with an increased risk of severe anaphylaxis were identified, higher age and concomitant mastocytosis being the most important predictors. Vigorous physical exercise, male sex, and psychological burden were more often shown to be related to severe reactions. In logistic regression analysis, intake of beta-blockers and ACE-I in temporal proximity to allergen exposition was identified as an essential factor.