Point prevalence of documented penicillin allergy among patients hospitalized in a German university hospital: implications for delabeling

Background With a global prevalence of 9.4%, penicillin allergy (PenA) is the most commonly documented drug allergy in hospitalized patients. Since over 90% of these labels cannot be confirmed, structured evaluation is crucial to optimize patient care. Prevalence data are available from several European countries, but data for Germany are lacking. This study provides data on the prevalence of PenA and cephalosporin allergy (CephA) as well as documentation quality from a large German university hospital. Methods Adult inpatients were screened on 10 days between November 2023 and February 2024, and pediatric inpatients were screened on five days in 2025; 29 adult and seven pediatric wards across various specialties were included. Primary outcome was the average point prevalence of documented PenA or CephA labels across predefined screening days. Secondary outcomes included documentation quality, reported reactions, and beta-lactam use. Results The mean point prevalence in adults was 8.1% for PenA alone and 8.7% for PenA or CephA (418 allergy labels/4777 screened records). Point prevalence was highest in general internal medicine (12.8%) and lowest in cardiac intensive care units (4.2%). In 65% of cases, no reaction was documented, and 70% of labels were unspecific. In the pediatric cohort, the mean point prevalence was 1.7% (8/477). Conclusion Our findings demonstrate substantial potential for improved allergy assessment and highlight the relevance of PenA evaluation in German hospitals. Targeting low-risk patients in higher prevalence wards may offer a practical approach, particularly when allocating resources to delabeling programs. Improved clinical awareness and consistent documentation could further support safe and sustainable PenA delabeling strategies.