Delabeling low-risk penicillin allergies in a Canadian family medicine clinic

Penicillin allergy is commonly reported; however, few individuals are truly allergic. This mislabeling is linked to adverse health outcomes and higher healthcare costs. Although direct oral challenge is a proven approach for delabeling low-risk penicillin allergy patients, there is limited evidence in primary care. This study assessed the uptake and safety of delabeling low-risk penicillin allergies with direct oral challenge in a Canadian family medicine clinic using a multidisciplinary team approach. This observational study included adults with a penicillin allergy listed in the electronic medical record of their family medicine clinic. Exclusions included a PEN-FAST score > 2, pregnancy, regular antihistamine use, blistering skin condition, significant neurologic or psychiatric conditions, unclear allergy history, or a history of anaphylaxis to other antibiotic classes. Eligible patients were offered a direct oral challenge with a single dose of amoxicillin 250 mg. We assessed the proportion of contacted patients who agreed to a screening appointment (uptake rate); proportion of screened patients delabeled; proportion of challenged patients delabeled; and immediate and delayed reactions. Among 3,500 clinic patients, 169 adult patients had a penicillin allergy listed. The uptake rate was 36% (58/160 patients); 45% of screened patients were delabeled (24/53 patients); and 92% of patients who underwent the direct oral challenge were delabeled (24/26 patients). No immediate reactions were observed. Three patients reported possible delayed reactions; two of whom were not delabeled. Delabeling low-risk penicillin allergies with direct oral challenge in primary care with a multidisciplinary team appears both feasible and safe. Further research is needed to explore implementation strategies and to determine whether delabeling in primary care provides clinical and economic net benefit.