Delabelling suspected amoxicillin allergy in pediatric patients using oral challenge: a retrospective study from Northwestern Ontario.

To determine the proportion of children labelled as allergic to amoxicillin who are truly allergic and to assess whether a direct oral amoxicillin challenge, without prior skin testing, is a safe and effective way to remove incorrect allergy labels in low-risk pediatric patients in Northwestern Ontario. We conducted a retrospective review of pediatric patients (6 months-15 years) referred for suspected amoxicillin allergy at two Northwestern Ontario hospitals between 2015 and 2025. Eligible patients underwent oral amoxicillin challenge. Clinical data were summarized descriptively. Of 96 patients, 93 (96.9%) tolerated the oral amoxicillin challenge, while 3 (3.1%) developed mild, delayed rashes. All three had previously reported delayed reactions (5-10 days) after their initial amoxicillin exposure. Two patients developed delayed rashes that were consistent with their previously documented maculopapular reactions, based on EMR documentation and caregiver-reported descriptions.

Conclusion

The prevalence of true amoxicillin allergy among low-risk pediatric patients carrying a reported "penicillin allergy" label in our cohort of 96 patients evaluated at our pediatric allergy clinics in Northwestern Ontario was 3.1%. Oral amoxicillin challenge without prior skin testing proved to be a safe and effective approach for delabelling low-risk children. Broader implementation of this strategy could enhance antibiotic stewardship, reduce healthcare-related costs, and improve patient care.