Implementing PEN-FAST for penicillin allergy delabeling in a high-prevalence population

Area of Science:

• Clinical Immunology
• Dermatology
• Infectious Diseases

Background:

• Self-reported penicillin allergies are common, leading to unnecessary broad-spectrum antibiotic use, antimicrobial resistance, and increased healthcare costs.
• Accurate identification of true penicillin allergies is crucial to avoid these negative consequences.

Purpose of the Study:

• To evaluate the PEN-FAST score's accuracy and safety in identifying low-risk patients for direct drug provocation tests (DPT) without prior skin testing.
• To assess the PEN-FAST score's negative predictive value (NPV) in a real-world clinical setting.

Main Methods:

• A single-center study involving patients with a penicillin allergy label between 2004 and 2024.
• Evaluation included skin testing, allergen-specific IgE, and direct drug provocation tests (DPT).
• The PEN-FAST score was used to stratify patients into low-risk and high-risk groups.

Main Results:

• Out of 189 patients, PEN-FAST identified 36.9% as low-risk.
• In a retrospective cohort, 66.4% of patients were successfully delabeled after DPT.
• The PEN-FAST score demonstrated a high NPV of 95.8%, comparable to formal allergy testing, with a low rate of misclassification.

Conclusions:

• The PEN-FAST score is a safe and feasible tool for identifying patients suitable for direct DPT, potentially reducing the need for extensive allergy workups.
• Implementing PEN-FAST can help safely delabel patients with penicillin allergies, leading to more targeted antibiotic prescribing.
• This study supports the use of PEN-FAST in clinical practice for managing patients with penicillin allergy labels.