Systemic reaction during intradermal skin tests with beta-lactams.

Beta-lactam (BL) antibiotics are the most frequent cause of drug hypersensitivity in children, inducing both immediate and non-immediate reactions. Here we report a case of a 4-year-old child with a disseminated maculopapular exanthema 7 days after the first dose of amoxicillin-clavulanate, referred to our paediatric allergy department. Skin prick tests were negative. Intradermal tests were performed and, after 10 hours, indurated wheals larger than 10×10 mm with progressive erythema and disseminated maculopapular eruption were developed, related to amoxicillin and amoxicillin-clavulanate. Systemic reactions to BL skin tests are rarely reported and the majority are immediate reactions. This case illustrates a rare example of a non-immediate systemic reaction to intradermal tests, underlying the importance of skin testing before drug provocation tests in cases of moderate to severe non-immediate reactions.