1093. Bypassing Penicillin Skin Testing in favor of Direct Oral Challenge: A Pharmacy-driven Inpatient Program

Abstract Background Patient interview, penicillin skin testing (PST) and/or an oral challenge can be used to evaluate penicillin allergies. Programs favor PST prior to oral challenge, but there is interest in bypassing PST and directly oral challenging for logistical and financial reasons. Data on the safety and efficacy of a direct challenge in the inpatient setting when the index reaction is moderate to severe (e.g. swelling of throat, angioedema, anaphylaxis) is lacking. Methods Adult patients (≥18 years) admitted with a penicillin allergy were evaluated for eligibility between September 2019 and June 2021. Pregnant patients were excluded, while critically ill patients and those on anti-histamine medications were evaluated if clinical need was high. Institutional protocols allowing for patients to be challenged without PST if reaction was more than 10 years ago were used. Data collected included the number of patients challenged and delabeled, number of patients who had moderate to severe index reactions, number of patients who were relabeled without cause, and number of patients who declined further testing. Results Two hundred twenty-five patients were evaluated; 11 patients declined testing. Two hundred four patients were delabeled (95%) among those fully evaluated. One hundred twelve patients were delabeled by interview and chart review alone (52%), 99 by oral challenge (46%), and 2 by PST and oral challenge (1%). Twenty-nine patients with moderate to severe reactions were challenged and 27 were delabeled. Ten patients could not be delabeled due to mild or delayed reactions to challenge or subsequent treatment, including 2 patients with severe index reactions who had mild challenge reactions and required no rescue medications. No patients required epinephrine during challenge. Five patients were relabeled and then delabeled again as no new reaction had occurred. Conclusion Penicillin allergies can be removed with a pharmacy-driven algorithm that prioritizes direct challenges when appropriate even when the index reaction was moderate to severe. Risks of a reaction are low, and reactions tend to be mild. Given well-documented benefits of delabeling patients for the patient and the institution, more hospitals should consider starting such services. Disclosures All Authors: No reported disclosures