Breaking the Barrier: Transforming the Diagnosis and Management of Penicillin and Cephalosporin Allergy in China: Prevalence, Diagnostic Challenges, and Implications for Public Health and Clinical Practice.

Background: β-lactam allergy labels are common in routine care but are variably verified. This manuscript assessed prevalence, clinical features, verification practices, and penicillin-cephalosporin cross- occurrence across multiple hospitals in China.

Methods: Multicenter cross-sectional questionnaire in outpatient clinics at 22 institutions (n=6,070). Adjudication relied on routine records and prior testing performed in care. "Clinically confirmed" allergy required a chart-documented reaction and/or a previously positive skin test; indeterminate entries were coded "uncertain." Cross- occurrence required confirmation for both classes. No de novo skin testing or drug provocation was performed by the study team; severe cutaneous adverse reactions were described without re-exposure. Descriptive statistics and χ² tests were used; logistic regression adjusted for prespecified covariates (age, sex, parental allergy history).

Results: Self-reported penicillin allergy was 21.9% (1,331/6,070); self-reported cephalosporin allergy was 4.5% (273/6,070). Among respondents reporting cephalosporin allergy, 28.9% (79/273) had skin-test positivity documented in routine care. Confirmed penicillin-cephalosporin cross- occurrence was 2.3% (140/6,070). Testing practices varied across sites, and drug provocation was generally not implemented.

Conclusions: In this multicenter survey adjudicated from routine care, clinically confirmed β-lactam allergy was substantially lower than self-report, and confirmed penicillin-cephalosporin cross- occurrence was uncommon (2.3%). Clear confirmation criteria and phenotype-based triage using existing documentation can support safe delabelling and more appropriate first-line β-lactam use; the accompanying SOP provides procedural detail for replication.