Necrotising fasciitis (NF)
Overview
Necrotising fasciitis is an uncommon, rapidly progressive infection of subcutaneous tissue and deep fascial planes with high morbidity and mortality. Early disease often mimics cellulitis. The clinical priorities in the emergency department are rapid recognition, resuscitation and immediate surgical escalation because early operative debridement is diagnostic and definitive (GOV.UK; RCEM).
Red flags (urgent surgical review)
- Severe pain out of proportion to visible skin findings.
- Rapidly spreading erythema, tense oedema or induration over hours.
- Systemic toxicity or sepsis: fever, hypotension, tachycardia, vomiting, altered mental state.
- New blisters or bullae, dusky or purplish skin discolouration, haemorrhagic bullae, necrosis, crepitus.
- Hyponatraemia in a septic patient is a suggestive laboratory finding (GOV.UK).
Immediate actions in the ED
- Triage with NEWS2 and treat as a potential time‑critical surgical emergency if red flags present (NICE NG253).
- Call the on‑call surgical registrar immediately for senior review and consideration of urgent theatre. Do not let imaging delay surgical referral or theatre (RCEM).
- Start resuscitation and sepsis care without delay:
- Give high‑flow oxygen as needed.
- Establish at least two large‑bore IV lines.
- Obtain urgent bloods: FBC, CRP, electrolytes (note sodium), creatinine, glucose, coagulation, lactate.