The prevalence of antibiotic skin test reactivity in a pediatric population.

Although adverse drug reactions (ADRs) are not uncommon, true allergic (i.e., immunologic) reactions are infrequent. Estimates are that only 10% of reported "penicillin (PCN)-allergic" patients have true allergic drug reactions. Most studies of PCN-related ADR have been conducted in adult populations and suggest that the majority of adult patients presenting with PCN allergy history can safely receive the drug. The goal of this study was to examine the outcome of provocative drug challenges to antibiotics in a pediatric population and correlate outcomes with predictive factors. Through chart review, we identified 96 pediatric patients with history of an ADR to antibiotics who underwent skin testing (ST) and/or graded challenges to PCN (n = 52), cephalosporins (n = 7), azithromycin (AZT; n = 24), or clindamycin (n = 4). Of these children with an ADR, 87 (90.6%) tolerated provocative drug challenges and 9 (9.4%) were instructed to continue drug avoidance because of positive ST or failed challenge. Eight of the nine patients continued drug avoidance due to positive PCN ST (n = 4) or ADR during drug PCN challenge (n = 4). All AZT and cephalosporin challenges had negative outcomes, and only one patient did not proceed with the clindamycin challenge after a positive ST. True "antibiotic allergy" denoted by positive ST or failed challenge in patients with a history of ADR occurred in <10% of children included in this study, suggesting that without such testing nearly 90% might be treated with alternative antibiotics unnecessarily.