PURPOSE OF THE STUDY.
To determine whether children with a diagnosed penicillin allergy were at increased risk for adverse drug reactions to cephalosporins.
The charts were reviewed of 173 Mayo Clinic patients (91 boys) under the age of 18 years (mean age, 4.1 ± 3.1 years) who had a history of penicillin allergy, and underwent penicillin skin testing, and subsequently took a cephalosporin.
This was a retrospective chart review of pediatric patients who exhibited symptoms consistent with IgE-mediated adverse reactions to penicillin. Penicillin allergy skin testing included skin prick and intradermal testing using penicillin, its major and minor determinants, and amoxicillin with appropriate positive and negative controls. A skin test wheal size of 3 mm or greater was considered positive. Patients were given cephalosporins from 1 to 160 months (median, 14 months) after their penicillin reaction.
A total of 21 (12%) patients tested positive to penicillin; 12 (57%) of them received a first-generation cephalosporin, and the remainder received second- through fourth-generation cephalosporins. None of the penicillin skin test–positive patients exhibited adverse drug reactions. Among the remaining 152 (88%) study patients who had negative penicillin skin testing results, a first-generation cephalosporin was given 59% of the time. Only 1 (0.7%) had an adverse drug reaction involving eyelid swelling in response to cephalexin about 6 years after his penicillin reaction.
Among 173 children with a history of penicillin allergy, only 1 child experienced an allergic reaction to a cephalosporin.
Literature cites about a 7% to 20% cross-reactivity of cephalosporins in penicillin-allergic patients, with first-generation cephalosporins like cephalexin having a higher risk of reaction due to side chain similarity. This article, which looked at 173 cases, provides some guarded reassurance that, in most cases, cephalosporins may be safely administered to children with a history of penicillin allergy. In addition, the 1 cephalosporin reaction in a child who tested negative for penicillin allergy should remind us that individuals may develop an allergy to the cephalosporin without penicillin allergy. However, the study is limited by the fact that children with positive tests who were never given cephalosporins (because of preconceived risks) would not have been included, and the risk is likely higher in this group as indicated in prior studies. Testing is available and should be pursued.
- Copyright © 2012 by the American Academy of Pediatrics