Epidemiology of erysipelas and necrotising soft tissue infections

INTRODUCTION. Erysipelas is a common disease in the emergency department, whereas necrotising soft tissue infections (NSTIs) are rare but more severe. The study aimed to investigate the prevalence, incidence, population-based incidence rate, one-year mortality and clinical presentation of erysipelas and NSTIs, and the aetiology, treatment and recurrence of erysipelas. METHODS. This was a population-based cohort study including acute non-trauma patients ≥ 18 years old with erysipelas or NSTIs from the Region of Southern Denmark in the period from 1 January 2016 to 19 March 2018. RESULTS. Among 223,618 acute non-trauma visits, 2,136 had erysipelas (prevalence 1%), and 20 had NSTIs (prevalence 0.01%), 96.7 and 0.89 per 10,000 visits, respectively. The population-based incidence rates were 72.10 per 100,000 person-years for incident cases of erysipelas and 0.94 for NSTIs. One-year mortality was 15% for erysipelas and 25% for NSTIs. Erysipelas and NSTI patients had similar demographics and vital signs. For erysipelas, the predominant pathogen in blood cultures was Streptococcus dysgalactiae, with two-thirds of patients treated with narrow-spectrum penicillin. One-third of the erysipelas patients had a prior hospitalisation for the condition, and 7.7% of incident cases had recurrence within one year. Obesity and liver disease were risk factors for recurrence. CONCLUSIONS. Erysipelas is a common infection in the emergency department, whereas NSTIs are much rarer but also more severe and, at presentation, not distinctive in clinical parameters, which underlines the importance of clinical judgement. FUNDING. None. TRIAL REGISTRATION. Not relevant.