Risk factors associated with the severity of systemic insect sting reactions.

To evaluate risk factors associated with the severity of systemic insect sting reaction and to determine the type of insect responsible for systemic anaphylaxis, we conducted a cross-sectional study of 498 patients undergoing venom immunotherapy for insect sting reaction in 13 allergy clinics in Israel. Data were collected by questionnaire and review of patient records. Eighty percent of the patients were treated with honeybee venom, which was used as a single therapy in 60% of the group. In a multivariate logistic model the major factors identified as significantly influencing the probability of a more severe systemic reaction were short time of onset of reaction after stinging (<30 min), high number of prior stings (> or = 4), and age (> or = 18 years). A total of 79.3% of the patients had been stung outdoors, and 50% had lived all their lives in rural areas as compared to 10% in the general Israeli population. This study reports clinically valuable risk factors for the severity of systemic sting reaction. A practical finding was that the honeybee is the insect mostly responsible for sting reactions in Israel, but the type of insect is not a significant predictor of the severity of the reaction.