Validation of the first risk stratification based penicillin delabeling program outside an allergy clinic in Norway

Background: Penicillin allergy is self-reported by 3-10% of patients admitted to hospital. The label is wrong in 90% of the cases and has severe health implications. Penicillin-delabeling can reverse the negative effects of the label, and pathways adapted to local practice are needed. No tools are available in Norway for penicillin delabeling outside an allergy clinic. Methods: An interdisciplinary taskforce created a penicillin allergy delabeling program (PAD) adapted to the Norwegian health care system. This was validated in a prospective, single-centre study. Very low-risk and low-risk patients underwent a direct oral penicillin challenge and high-risk patients were referred for allergologic evaluation. Results: 149 patients declaring penicillin allergy were included. Seventy-four (50%) were very-low- and low risk patients suitable for a direct oral penicillin challenge resulting in only one mild reaction. 60 high-risk patients were eligible for an oral penicillin challenge after allergologic evaluation, three patients reacted non-severely. Conclusion: We have demonstrated excellent repeatability and feasibility of the first PAD applicable in a hospital setting outside an allergy clinic in Norway. Our data suggests this is safe and beneficial, with 49% patients delabeled through a direct oral penicillin challenge, performed without any serious adverse events, and an overall 87% delabeling rate.