Is an amoxicillin oral provocation challenge safe and accessible for distinguishing an erroneous penicillin allergy label from a true one in adults and children?
This study reports the outcome of an amoxicillin oral provocation challenge (OPC) in 99 adults and children who were initially labeled as having a penicillin allergy and were subsequently identified by their history to be at low risk of a true allergy. A total of 96 patients (97%) completed the OPC with no reaction, resulting in removal of the erroneous allergy label. The 3 reactions were all mild and required minimal intervention (no epinephrine). Having primary care clinicians use this method to identify the millions of adults and children who are incorrectly labeled as having a penicillin allergy may result in significant health care savings from the use of less effective, more expensive, and/or less safe alternative antibiotics.
Self-funded or unfunded
Although approximately 10% of adults and children are labeled as having an allergy to penicillin, less than 20% of those are truly allergic. Referring the millions of adults labeled as allergic to penicillin for testing is not practical. However, an easy rule is available that can identify adults* at low risk of a true allergy. These investigators, using similar criteria as those in the decision tool, identified 99 adults and children, 18 months or older, considered at low risk (< 5%) of having a true penicillin allergy. Clinical settings were equipped with oral diphenhydramine elixir to manage mild reactions and epinephrine to manage anaphylactic reactions. Amoxicillin was given as an oral suspension (250 mg/5 mL) with the first 10% of the challenge dose (50 mg or 4.5 mg/kg if the patient weighed < 10 kg) and the patients were observed for 20 minutes. If there was no reaction, patients received the remaining 90% of the remaining calculated dose (450 mg or 40.5 mg/kg) and were observed for an additional hour. A positive reaction was the development of objective findings, including urticaria, wheezing, or swelling, and did not include subjective symptoms such as pruritus without skin changes or dizziness. Patients were also instructed to report any delayed symptoms of rash, hives, wheezing, or swelling up to a week later.
Of the 99 eligible patients who completed the protocol, a mild reaction occurred in 3 patients (3%) and required the administration of oral diphenhydramine only. The remaining 96 patients (97%) had the penicillin allergy label removed from their medical record. No delayed reactions were reported.
*Note: Although the adult version is reliably accurate, the same is not true when using the same decision rule for children 12 years or younger.
David C. Slawson, MD
Professor and Vice Chair of Family Medicine for Education and Scholarship
Professor of Family Medicine, UNC Chapel Hill