Non-immediate hypersensitivity reactions to beta-lactam antibiotics in children - our 10-year experience in allergy work-up

Background Non‐immediate reactions to beta‐lactam antibiotics (BL) occur more than one hour after drug administration, and the most common manifestations are maculopapular exanthemas and delayed‐appearing urticaria and/or angioedema. Infections can lead to skin eruptions and mimic drug hypersensitivity reactions (DHR), if a drug is taken at the same time. The most of children are labeled as ‘drug allergic’ after considering only the clinical history. Objective To diagnose/detect a hypersensitivity or an infection which mimic DHR in children with non‐immediate reactions to BL Methods A prospective survey was conducted in a group of 1026 children with histories of non‐immediate reactions to BL by performing patch tests, skin tests, and in case of negative results, drug provocation tests (DPTs). In 300 children, a study was performed to detect infections by viruses or Mycoplasma pneumoniae. Results Urticaria and maculopapular exanthemas were the most reported non‐immediate reactions. Only 76 (7.4%) of 1026 children had confirmed non‐immediate hypersensitivity reactions to BL. Fifty‐seven children had positive delayed‐reading intradermal tests (18 of these with a positive patch test). Nineteen children had positive DPT. Sixty‐six of 300 children had positive tests for viruses or Mycoplasma pneumoniae and 2 of them had a positive allergy work‐up. Conclusions A diagnostic work‐up should be performed in all children with non‐immediate reactions to BL, to remove a false label of hypersensitivity. Even though only 57 (5.5%) of 1026 children displayed positive responses to delayed‐reading intradermal tests to BL, such tests appear to be useful in order to reduce the risk for positive DPTs.