Symmetrical Drug-Related Intertriginous and Flexural Exanthema With Amoxicillin: Presenting a Flare-Up Phenomenon

This case report describes a 40-year-old male patient who developed symmetrical drug-related intertriginous and flexural exanthema after taking amoxicillin. Initial allergy testing showed negative intradermal tests, but subsequent drug provocation tests with amoxicillin and penicillin were positive, indicating cross-reactivity between these β-lactam antibiotics. Notably, following the final provocation test, the intradermal test with penicillin turned positive, demonstrating a flare-up phenomenon. The findings highlight the importance of thorough allergy evaluations, including drug provocation testing, to guide safe antibiotic treatment.