Non-purulent skin and soft tissue infections: predictive power of a severity score and the appropriateness of treatment in a prospective cohort.

Skin and soft tissue infections (SSTIs) are increasing. Frequent over- and under-treatment has been reported, including non-purulent SSTIs where cases demanding surgery or broad-spectrum therapy often are hard to identify. Our aim was to measure the predictive power of a modified severity score and use it to identify areas of improvement in antimicrobial therapy of non-purulent SSTIs. We prospectively included adult patients admitted to hospital with non-purulent SSTIs. A modified Dundee score at admission was calculated retrospectively, and associations between severity and outcomes were analysed. We evaluated appropriateness of treatment in relation to severity scores, and assessed adverse effects of broad-spectrum therapy. We included 200 cases with cellulitis and 19 cases with necrotising soft tissue infections (NSTIs). Thirty-two per cent were categorised as severity class I, 15% as class II, 28% as class III and 25% as class IV (most severe). In class I, 66 out of 69 cases did not have a complicated course. All but one NSTI case were identified by the class IV criteria. Over-treatment was common and mostly seen in class I. Broad-spectrum antibiotics or clindamycin use was associated with an increased risk of diarrhoea. Prolonged treatment (>14 days) was associated with age, severity and surgery. The modified Dundee score proved valuable in identifying those with the lowest risk of complication and the most severe infections, and could serve as a useful clinical tool in the emergency department. Frequent over-treatment and associated adverse effects were confirmed, underscoring the need for improved risk assessment.