Allergy to betalactams in children: diagnosis of non-immediate hypersensitivity by means of skin tests and oral challenge.

Purpose. - Studies have shown that late responses are obtained in skin test s in patients experiencing non-immediate reactions during betalactam treatm ents. However, in a recent study in children, we have shown that most cases of non-immediate hypersensitivity were diagnosed by oral challenge with th e suspected betalactams. Thus, we aimed to compare the clinical and demogra phic characteristics of subgroups of children diagnosed as having non-immed iate hypersensitivity to betalactams by means of skin tests and oral challe nge respectively. Methods. - Pricks and intradermal tests were performed with soluble betalac tams. The response was assessed at 20 minutes, 6-8 hours and 48-72 hours. O ral challenges (OC) were performed in children with negative skin tests. No n-immediate responses in skin tests and non-immediate reactions in oral cha llenge were observed in 41 of 500 children (8.2%), including one child repo rting reactions to several betalactams. Thus, responses in skin tests and o ral challenge led to the diagnosis of non-immediate hypersensitivity in 24. 4% and 78% of the children respectively. Most of the children diagnosed as allergic by skin tests reported accelerated urticaria and angioedema. In co ntrast, the children diagnosed as allergic by oral challenge reported vario us reactions, and most of these reactions were delayed (P < 0.05). Conclusion. - Thus, our results suggest that accelerated allergic urticaria and angioedema diagnosed by means of skin tests result from non-immediate hypersensitivity to native or poorly metabolized betalactams. In contrast, most delayed reactions, including urticaria and angioedema, maculopapular a nd unidentified rashes, were diagnosed by oral challenge, suggesting that t hese reactions probably result from delayed-type hypersensitivity to metabo lites of betalactams. (C) 2001 Editions scientifiques et medicales Elsevier SAS.