Health outcomes of penicillin allergy testing in children: a systematic review

BACKGROUND: Penicillin allergy labels are commonly acquired in childhood and lead to avoidance of first-line penicillin antibiotics. Understanding the health outcomes of penicillin allergy testing (PAT) can strengthen its place in antimicrobial stewardship efforts. OBJECTIVES: To identify and summarize the health outcomes of PAT in children. METHODS: Embase, MEDLINE, Web of Science, Cochrane Library, SCOPUS and CINAHL were searched from inception to 11 Oct 2021 (Embase and MEDLINE updated April 2022). Studies that utilized in vivo PAT in children (≤18 years old) and reported outcomes relevant to the study objectives were included. RESULTS: Thirty-seven studies were included in the review, with a total of 8411 participants. The most commonly reported outcomes were delabelling, subsequent penicillin courses, and tolerability to penicillin courses. Ten studies had patient-reported tolerability to subsequent penicillin use, with a median 93.6% (IQR 90.3%-97.8%) of children tolerating a subsequent course of penicillins. In eight studies, a median 97.3% (IQR 96.4%-99.0%) of children were reported as 'delabelled' after a negative PAT without further definition. Three separate studies verified delabelling by checking electronic or primary care medical records, where 48.0%-68.3% children were delabelled. No studies reported on outcomes relating to disease burden such as antibiotic resistance, mortality, infection rates or cure rates. CONCLUSIONS: Safety and efficacy of PAT and subsequent penicillin use was the focus of existing literature. Further research is required to determine the long-term impact of delabelling penicillin allergies on disease burden.