Necrotising Fasciitis
Necrotising fasciitis is an uncommon but rapidly progressive and life-threatening infection soft tissue infection involving the deep dermis, subcutaneous fat and fascia.
This updated UKMLA guide to necrotising fasciitis is based on PCDS and BOASt guidance, which covers causes, symptoms, diagnosis and management.
Causes
Most commonly caused by group A streptococci (Streptococcus pyogenes)
Necrotising fasciitis may develop as a complication of cellulitis or present as a rapidly progressive soft tissue infection from the outset.
Clinical Features
Typical presentation:
- Pain – that is severe and is out of proportion to the clinical findings
- Diffuse erythema
- Purple skin discolouration (dusky-violaceous)
- Palpable crepitus (from gas produced by the bacteria)
- Blisters → necrotic tissue
- Severe systemic toxicity
Necrotising fasciitis may initially present as suspected cellulitis that is rapidly worsening or not responding to antibiotics.
Necrotising fasciitis most commonly affects the lower limbs.
It may also affect other body regions, including:
- Genital and perineal area (Fournier gangrene) – rare but associated with diabetes and SGLT-2 inhibitors
- Abdomen
- Upper limb
Investigation and Diagnosis
Diagnosis is primarily based on clinical suspicion
- Necrotising fasciitis is a surgical emergency – ALL suspected cases should be referred and treated in hospital urgently
- Management should not be delayed awaiting investigations (e.g. blood cultures, routine blood tests)
Definitive diagnosis is usually made during surgical exploration and deep tissue biopsies.
Management
2 most important immediate management:
- Immediate surgical debridement (definitive management) – NOT to be delayed by medical management or investigations
- IV broad spectrum antibiotics to be started ASAP
In practice, management occurs simultaneously:
- Urgently escalating to and involving the surgical team
- Preparing the patient for emergency surgical debridement
- Commencing IV broad-spectrum antibiotics as soon as possible, without delaying surgery