Are current strategies for penicillin allergy prediction ready for implementation?

Published online July 20, 2024

The issue of penicillin allergy mislabeling is a critical concern in contemporary medicine, as up to 99% of subjects labeled as penicillin-allergic can, in fact, tolerate these antibiotics. Current strategies for delabeling focus on reviewing clinical histories to identify low-risk subjects who can safely undergo direct penicillin challenges. The development and validation of reliable tools that can assess patient risk for an allergic reaction, therefore facilitating labeling and delabeling of penicillin allergies, have been widely advocated to support clinical practice and antibiotic stewardship programs. But are these tools ready for general application?

The primary objective of the retrospective study conducted by Ghiordanescu et al. and published in The Journal of Allergy and Clinical Immunology: In Practice was to compare the effectiveness, in terms of delabeling performance and safety, of four penicillin allergy prediction strategies. These were derived from studies conducted in the United States (as reported by Blumenthal et al.), Australia (the PEN-FAST score, introduced by Trubiano et al.), and Europe (two distinct strategies detailed by Romano et al. and Chiriac et al.). The strategies were applied on a French cohort of 1884 subjects with previous reactions to penicillins who were investigated for penicillin allergy by skin tests and drug challenges at the Central University Hospital of Montpellier.

The Romano and Blumenthal strategies were safe for individuals deemed as high-risk based on the semiology of the reaction they had to penicillins in the past but had limited delabeling effectiveness. This led to increased unnecessary avoidance of penicillins. In contrast, the PEN-FAST and Chiriac strategies showed better delabeling performance but missed more cases of high-risk patients who returned positive allergy tests, generating the potential for adverse outcomes upon re-exposure. None of these strategies achieved an ideal balance between minimizing the risks of a new reaction during medically supervised re-exposure to penicillins and preventing unnecessary penicillin avoidance. Consequently, choosing the right tool for clinical application requires careful evaluation of the target population and desired outcomes, such as patient selection for direct challenges in non-specialist clinics and triage in drug-allergy clinics, or guidance for non-specialists and pharmacists during specialist referrals.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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