Penicillin Allergy Testing with Direct Oral Challenge in Primary Care.

Purpose: 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.

Methods: 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.

Results: 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.

Conclusions: 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.