Identifying and De-Labeling Inappropriate Penicillin Allergies at a Primary Care Clinic: A Student-Driven Feasibility Study

Poster #: 078
Session/Time: A
Author: Robert Christian Busch Jr, BS
Mentor: John E. Snellings, MD
Research Type: Clinical Research

Abstract

INTRODUCTION:
Penicillin is one of the most common reported drug allergies in the U.S., though evidence shows many cases are not true IgE-mediated reactions. Mislabeling often stems from factors such as misattributing infection symptoms, over reliance on family history, or non-IgE reactions from rapid drug administration; even true IgE-mediated penicillin allergies diminish over time. All these factors contribute to worse health outcomes for patients and poor antibiotic stewardship. Recent efforts have focused on expanding penicillin allergy de-labeling initiatives into primary care settings. This student-led initiative evaluated the feasibility of primary care based de-labeling and the role of medical students in coordinating such efforts.

METHODS:
Patients with documented penicillin related antibiotic allergies were identified on the daily schedule of the EVMS Ghent Family Medicine clinic. During the visit, consenting patients completed a standardized allergy questionnaire administered by a medical student, including the PEN-FAST tool to assess risk of future IgE-mediated penicillin reactions. Patients with a score of 0 were considered very low-risk (<1%) for true penicillin allergy if their reaction was non-severe, cutaneous only, occurred over 5 years ago, and required no treatment. These patients were deemed eligible for de-labeling without further testing. Patients with PEN-FAST scores of 1-2 (<5% risk) were considered low-risk and eligible for future direct oral challenge (DOC) with amoxicillin to confirm their status.

RESULTS:
A total of 62 patients were approached, with 54 consenting to take the questionnaire (87.10%). Subjects with a very low-risk PEN-FAST score was the most common (n=20, 37.04%) followed by low-risk (n=18, 33.33%). Among those qualifying for DOC, 11 subjects expressed interest in DOC (61.11%). Logistic regression analysis showed that subject PEN-FAST score was not statistically significant as a predictor for patient openness to taking penicillin in the future (p = 0.2413). However, PEN-FAST score was a statistically significant predictor for openness to DOC, with each 1-point increase in PEN-FAST score associated with a 34% reduction in the odds of willingness to undergo DOC (OR = 0.66, 95% CI: 0.43-0.99, p = 0.0485). The overall model was significant (χ² = 4.18, df = 1, p = 0.041), indicating that higher PEN-FAST scores are linked to greater hesitancy toward DOC.

CONCLUSION:
These findings support the feasibility of a student-led penicillin allergy de-labeling initiative in a primary care setting, with 87.10% of patients consenting to participate and 61.11% of qualifying subjects open for future DOC. Furthermore, 57.41% of participants assessed with PEN-FAST were either safely de-labeled immediately or expressed willingness to undergo DOC, underscoring the potential impact of these efforts. While PEN-FAST scores stratify clinical risk, they did not consistently predict patient willingness to be open to taking penicillin. PEN-FAST scores did predict openness to DOC, however. This difference in predictability most likely is due to small sample size as this is a change from previous findings. Overall, the results demonstrate that medical students can successfully lead allergy de-labeling efforts, and a significant number of patients are willing to take the next steps, with potential for broader implementation in the future.