Cephalosporins Should be Avoided in Patients with Penicillin Allergy.

There has long been concern regarding cross-reactivity between penicillin and cephalosporin allergies, with historical sources citing rates up to 10%. More recent assessment of later-generation cephalosporins suggests a cross-reactivity rate closer to 1%. Clinical guidance is inconsistent, with some advising blanket avoidance of cephalosporins, whereas more recent specialist guidance supports a nuanced, risk-stratified approach. Shared decision-making and individual risk assessment are recommended, with a role for formal allergy testing and incremental dosing in some cases.