To prospectively determine the incidence of Hymenoptera stings in children <5 years.

This is a prospective longitudinal observational study of Irish newborns from the BASELINE Cohort Study. This study included 2137 newborn infants who were recruited from 2008 to 2011 and managed until 5 years of age.

Trained researchers administered questionnaires at 6 months, 12 months, 2 years, and 5 years of age. The questionnaires were used to inquire about the occurrence of sting events. At ages 2 and 5 years, all children were seen for visits and underwent skin prick testing (SPT) to bee, Vespula, and 9 other common allergens. A positive test result was a wheal 3 mm or greater, with histamine as a positive control. If the SPT result was positive or the children reported a history of a sting event, allergy-specific immunoglobulin E (spIgE) was collected.

Of the 2137 newborns identified, 1226 were managed for the complete 5 years. At 6 months, 6 of 1809 (0.33%) children reported sting events. At 1 year, 16 of 1691 (0.9%) children reported sting events. At 2 years, 77 of 1209 (6.8%) children reported sting events. SPT was performed at age 2, with 11 positive results out of 1232 tests (0.89%). At 5 years, 268 of 1226 (21.9%) had reported sting events with 0 systemic reactions. SPT was performed at age 5, with 4 of 937 (0.4%) children having positive test results. None of the children that had positive SPT results at age 2 had positive results at age 5. Thirty-nine children underwent spIgE testing, with only 2 having positive results (5.1%). Of the 2 patients who tested spIgE positive, 1 had a history of a sting event without reaction and negative SPT result, and the other had a positive SPT result at age 2 years that was negative by age 5 without a sting event. Children who had a positive SPT result (62.5%) to bee or wasp were found to have a higher rate of allergic sensitization to aeroallergen and food in comparison with children with negative SPT results (23.8%). Of the total 367 sting events, 10 stings (2.7%) were systemic reactions reported by the parents that did not require evaluation or treatment by a physician.

Hymenoptera sting incidence increases with age. A positive SPT result does not correlate with sting history and does not predict venom allergy in patients who have not been stung. Venom SPT should not be performed in the general preschool-aged population.

This study highlights the low incidence of Hymenoptera sting events and reactions in the general preschool population. The findings confirm that “screening” tests for venom allergy should not be performed in the preschool population because results do not correlate with clinically significant reactions. Testing should be reserved for those with a clinical history suggestive of venom hypersensitivity, consistent with existing recommendations.