Update on penicillin allergy delabeling.

PURPOSE OF REVIEW To review phenotyping and risk classification of penicillin allergy and provide an update on penicillin allergy delabeling strategies for primary care. RECENT FINDINGS Beta-lactams are considered the treatment of choice for a wide range of bacterial pathogens; however, many patients receive second-line agents due to being labeled as having an allergy to penicillin. This approach can lead to antibiotic resistance and inferior health outcomes. While 10% of the population is labeled as penicillin allergic, penicillin anaphylaxis occurs in less than 1% of patients. For patients with delayed benign skin rashes (e.g., urticaria or maculopapular exanthem >1 h after administration) attributable to beta-lactam administration occurring more than 12 months ago, direct oral challenge (rechallenge with antibiotic in the clinical setting) can be a safe and effective strategy, with immediate reactions occurring in less than 5% of such low-risk patients and delayed reactions appearing infrequently. In patients with penicillin-associated immediate urticaria, other IgE-mediated features, or anaphylaxis, further allergy evaluation and penicillin skin testing is warranted. Any severe idiosyncratic cutaneous adverse reaction is rare, but can be dangerous so prompt removal of the inciting agent is required. SUMMARY Penicillin allergy delabeling is a high-value service that can be effectively delivered through a multidisciplinary collaborative approach.