IgE-mediated hypersensitivity to clavulanic acid, a rare pediatric condition?

Selective hypersensitivity to clavulanic acid is continuously increasing in recent decades due to the increase in its consumption. The allergological work-up is complex, mainly based on clinical history, followed by skin testing, and drug provocation test. The low sensitivity of in vitro tests is explained by the fact that clavulanic acid is highly metabolised into different products, with heterogeneous immunogenicities, being only some of them optimally recognised by the immune system. We report the case of a young girl who received one tablet of amoxicillin-clavulanic acid and developed immediate anaphylaxis, although she had previously tolerated amoxicillin. Immediate-reading skin tests performed with amoxicillin and cephalosporins were negative. A selective allergy to clavulanic acid was diagnosed by a positive response in skin tests with amoxicillin-clavulanic acid and tolerance of a provocation test with amoxicillin. No cross-reactivity was recorded between clavulanic acid and others beta-lactams.