SRS58 - The hidden cost of patient-reported penicillin allergy: a 2-year retrospective analysis of animal bite injuries

Design, setting and outcomes This is a retrospective cohort study of 307 adult patients presenting with upper limb animal bites to a UK tertiary plastic surgery unit conducted between January 2023 and January 2025. Primary outcomes were length of stay, requirement for formal debridement in theatre and escalation beyond initial management plan: delayed admission, readmission or conversion from nonoperative to operative management. Results Multivariable models included age, delay in initial debridement, anatomical site, co-morbidities and antibiotic regime. Significant predictors of longer admission included increasing age (P < 0.001), delay in initial debridement (P = 0.003), and treatment with non-penicillin-based antibiotics (P = 0.010). The incidence of surgical debridement was significantly increased by age (P = 0.002), delay in initial debridement (P = 0.020) and treatment with non-penicillin-based antibiotics (P = 0.022). Treatment with non-penicillin-based antibiotics significantly increased the likelihood of escalation beyond initial management plan (P = 0.001). Patients receiving non-penicillin-based antibiotics (n = 35, 11%) had a 27% longer admissions, were nearly three times more likely to require formal debridement in theatre and were seven times more likely to require escalation beyond initial management plan. The mean per-patient cost was £547 when treated with co-amoxiclav and £1288 when treated with non-penicillin-based alternatives. Conclusions and relevance In adults with upper extremity animal bites, older age, delay to initial debridement and treatment with non-penicillin-based antibiotics were associated with worse clinical outcomes. These findings support prioritising timely debridement and identify patient-reported penicillin allergy as a potentially modifiable factor with clinical and economic consequences.