Penicillin Allergy Testing with Direct Oral Challenge in Primary Care

Nearly 10% of the United States population has a reported penicillin allergy. However, many of these patients do not have true IgE-mediated allergy and are exposed to alternative antibiotics with increased risks of adverse outcomes, highlighting the importance of penicillin allergy testing. Patients with very low-risk penicillin allergies can safely undergo direct oral challenge (DOC) with a therapeutic dose of amoxicillin without prior skin testing. This study sought to establish a protocol for DOC in a primary care setting and test its efficacy and safety.

A standardized DOC protocol was developed at 2 primary care sites in Southeast Michigan. Forty-nine patients across the 2 sites were identified as having very low-risk penicillin allergies and underwent DOC. Follow up phone calls were completed 1 week and 6 months following DOC.

All 49 patients had a negative DOC and successfully had their penicillin allergy delabeled from their electronic health record (EHR). No patients reported severe adverse reactions following DOC. All 22 patients who were successfully contacted 6 months after completing DOC reported willingness to take penicillin if prescribed in the future and believed they were no longer allergic to penicillin.

The results suggest that DOC may be effectively and safely implemented in a primary care setting to delabel penicillin allergies in patients with low-risk penicillin allergies. This study may serve as a model to increase access to DOC for adults in rural settings or low-income patient populations with limited access to allergy specialists.