2025 Southeastern Residency Conference

Title: Unraveling Allergies: Evaluating the Impact of a Penicillin Allergy Clarification Service


Authors: Anny Nguyen, Caitlin Ellis, Melissa Padgett, Colleen Courey


Objective: To evaluate the incidence of patients with low risk penicillin allergies to determine the potential benefit of implementing a direct oral challenge service.


Background: Many penicillin allergies are often misreported and are associated with antimicrobial resistance, poor health outcomes, increased length of stay, and increased healthcare costs. The incidence of a true penicillin allergy may be falsely elevated due to initial false labeling of allergies or age-related decline in sensitization. Therefore, the introduction of an allergy de-labeling program may be beneficial for patients with reported penicillin allergies.


Methods: This is a single-center, observational study conducted at a 515-bed academic hospital. Pharmacy surveillance software was utilized to identify adult patients with a documented allergy or intolerance to a penicillin antibiotic who were within 24 hours of hospital admission. Patients were then interviewed for allergy clarification. Exclusion criteria included those unwilling or unable to participate in the patient interview. The primary endpoint was the incidence of penicillin allergy de-labeling. The secondary endpoints included the number of patients appropriate for a direct oral challenge, based on their PEN-FAST scores, the total time spent on the intervention, and the 30-day readmission rate.


Results: Interviews were conducted between September 2024 to December 2024. In total, 244 patients were included in the study. Of these, 44 patients (18.0%) had their penicillin allergy de-labeled following an allergy clarification interview, which determined that their previous reaction was not a true allergy or that they had tolerated a penicillin-class drug since the initial reaction. Additionally, 164 patients (67.2%) were deemed suitable for a direct oral challenge. On average, each interview lasted 8.2 minutes, and 65 patients (26.6%) were readmitted within 30 days at our facility.


Conclusion: The allergy interviews have proven valuable in clarifying patients' true penicillin allergies and updating their medical records as necessary. This study suggests the implementation of a direct oral challenge service at this institution may be beneficial given the high incidence of patients with low risk penicillin allergies.