Localized pustulosis induced by betalactams.

Abstract

Localized forms of pustular drug eruptions related to antibiotics are uncommon and their mechanism is still unknown. We describe herein a patient who developed numerous pin-head pustules without erythema in the peribuccal area after ingestion of ceftibuten and amoxicillin. The relationship with these drugs was confirmed by single-blind oral challenges. The following tests were performed: prick and intradermal tests with benzylpenicilloyl polylysine, minor determinant mixture, benzylpenicillin and amoxicillin; patch tests were also carried out with benzylpenicillin, amoxicillin, cloxacillin, cefuroxime, ceftriaxone, cefazolin, ceftibuten and cefaclor. All cutaneous tests were negative. Controlled single-blind challenge tests were performed with amoxicillin, cefadroxil, ceftibuten, cefuroxime, cefaclor, erythromycin and ciprofloxacin. All betalactam antibiotics tested gave a positive reaction, with good tolerance of other antibiotics; this would appear to indicate a specific mechanism of hypersensitivity and not an unspecific reaction to wide spectrum antibiotics.