Hypersensitivity to beta-lactam antibiotics: a three-year study.

BACKGROUND: Beta-lactams antibiotics (BL) are the most frequent elicitors of allergic drug reactions. The aim of our study was to characterize the patients referred with suspected hypersensitivity (HS) to BL. METHODS: Over a three-year period (2011-2013), a total of 234 adult and paediatric patients (pts) with suspected HS to BL were investigated according to the European Network for Drug Allergy guidelines. RESULTS: HS to BL was confirmed in 43 pts (18%), without differences between adult and paediatric pts; anaphylaxis was reported by 20 pts. Diagnosis was ascertained by: serum-specific IgE antibodies in 5 pts (12%), skin prick tests in 5 (12%), intradermal tests in 25 (58%), 3 with delayed reading, and the remaining 8 (18%) by drug provocation tests. Penicillins / derivatives were the culprit drugs in 39 pts, mainly amoxicillin, and cephalosporins in 4. CONCLUSION: In most of these patients with suspected HS to BL, allergological work-up was negative and HS was excluded. One fourth of confirmed cases had a plausible non-IgE mediated mechanism.