Cefazolin as an alternative in patients with a history of penicillin or β-lactam antibiotic allergy: A case overview

Many patients with suspected or confirmed allergy to penicillin or β-lactam antibiotics are unnecessarily denied all β-lactam antibiotics (BLA) and instead given a less effective antibiotic with more side effects. However, cefazolin, a first-generation cephalosporin, is a safe and effective treatment option for these patients in most cases. Recent studies show that immunological cross-reactions among BLAs are primarily caused by structural similarities in the side chains and not by the common β-lactam ring. Cefazolin has unique R1 and R2 side chains that largely rule out cross-reactivity with other BLAs. In a case series, 21 patients with a history of alleged or confirmed allergy to BLAs were exposed to cefazolin under real-life conditions, and all but 1 patient (who developed an uncomplicated maculopapular rash) showed no reaction. Therefore, the use of cefazolin is acceptable under clinical supervision in cases of a previous uncomplicated delayed-type reaction. However, in cases of reported or documented clinical reactions to BLA that are indicative of a type I allergy (such as urticaria, angioedema, anaphylaxis), prior to (titrated) administration of cefazolin under appropriate monitoring measures, a diagnostic evaluation in accordance with guidelines, including a negative skin test for cefazolin, is advisable. This procedure avoids the use of less suitable reserve antibiotics and ensures effective treatment without incalculable risk for anaphylaxis.