A Nurse-Led, Protocol-Driven Penicillin Allergy Evaluation from the Hong Kong Drug Allergy Delabelling Initiative: Effectiveness, Safety and Real-World Outcomes

Abstract

ationale There is a high prevalence of misdiagnosed penicillin ‘allergy’, associated with a multitude of adverse clinical outcomes. With the overwhelming burden of incorrect labels and lack of allergy specialist services, new delabelling strategies are urgently needed. We compared the effectiveness, safety and real-world outcomes of a nurse-led, protocol-driven evaluation of penicillin allergy – Hong Kong Drug Allergy Delabelling Initiative (HK-DADI). Methods Patients with suspected penicillin allergy were recruited into HK-DADI. Allergy and post-delabelling outcomes were compared between patients evaluated via HK-DADI or traditional allergist evaluation. Results Three-hundred-and-twelve patients completed penicillin allergy evaluation: 84 (27%) and 228 (73%) via HK-DADI and traditional pathways, respectively. Overall, 280 (90%) penicillin ‘allergies’ were delabelled. Delabelling rates of HK-DADI and traditional pathways were similar (90% vs 89%, p=0.796). Among patients of the HK-DADI pathway, the delabelling rate was significantly higher among low-risk (LR) than non-LR patients (97% vs 77%, p=0.010). Skin tests did not add diagnostic value among LR patients. No patients developed severe or systemic reactions during evaluation. Upon 6–12-month follow-up (median 10 months), 123 (44%) patients experienced infective episodes which required antibiotics and 63 (23%) used penicillins again after delabelling. This proportion was significantly higher in patients who were delabelled via HK-DADI than the traditional pathway (32% vs 19%, p=0.026).