UC San Diego

Abstract Background Rates of penicillin allergy mislabeling (PAM) are prevalent and lead to suboptimal antibiotic selection. However, data regarding PAM are lacking for people with HIV (PWH). We aimed to characterize the penicillin allergy labels for PWH at the University of California, San Diego’s (UCSD) HIV primary care clinic, evaluate the impact of penicillin allergy labels on treatment choice for syphilis and gonorrhea, and implement a quality improvement project to address PAM. Methods We conducted a cross-sectional study of PWH with a penicillin allergy label in their medical record who were seen in our clinic between 2018 and 2022. We collected demographic information, type of allergic reaction listed, whether patients tolerated other beta-lactam antibiotics, whether patients were referred for formal Allergy consultation, and, where relevant, what treatment they received for syphilis and/or gonorrhea. Results Among the 4,702 people with HIV receiving care in our clinic between 2018 and 2022, 427 (9.1%) had a penicillin allergy label in the medical record. This cohort reflected the demographics of the general clinic population (Table 1). Even though the majority of allergic reactions (327, 77%) were labeled as IgE-mediated, 282 (66%) patients tolerated another beta-lactam antibiotic (Table 2). Referrals to Allergy Clinic were rare (52, 12%). The majority of patients with syphilis (91/140, 65%) received 2nd line therapy with doxycycline. However, most patients with gonorrhea (65/88, 74%) were treated with a preferred ceftriaxone-based regimen. When relevant, we updated penicillin labels for 209/268 (77.9%) patients to indicate that they had tolerated other beta-lactam antibiotics and created a tiered referral process to prioritize the highest-risk patients for Allergy Clinic referral (Figure 1). Conclusion Penicillin allergy labels were prevalent in our cohort of PWH and often resulted in receiving 2nd line therapy for treatment of syphilis. We updated allergy labels for a substantial number of patients and created a triage system to refer patients to Allergy clinic for further testing based on risk in order to decrease PAM. Disclosures All Authors: No reported disclosures.