Drug hypersensitivity in children.

Drugs and their metabolites may act as haptens resulting in hypersensitivity reactions. These reactions occur less frequently in children than adults. As most pathogenetic mechanisms of drug hypersensitivity reactions (DHRs) and drug metabolic pathways are unknown, there are few diagnostic tests for DHRs. The patient's history, with particular emphasis on the type of reaction invoked by the drug is therefore, still of utmost importance in evaluation. Diagnostic tests are confined mainly to IgE-mediated DHRs, of which tests for penicillin allergy is the most established. Several factors are known to influence the occurrence of DHRs. Anaphylaxis is less common with orally administered drugs compared to those administered parenterally, and atopic persons appear to have an increased susceptibility to anaphylactic reaction. In the paediatric population, antibiotics, especially the penicillins, are common agents involved in DHRs. However, the fine erythematous macular papular rash frequently evoked by ampicillin, should not be mistaken for an allergic reaction with the associated risk of anaphylaxis. Other drugs commonly involved in DHRs in children are sulfonamides, aspirin, and vaccines, especially those against measles, mumps and rubella.