Presentation of necrotising skin and soft tissue infections

Clinical features that suggest a necrotising skin and soft tissue infection include:

• constant severe pain, even if skin inflammation is initially limited
• bullae
• skin necrosis or bruising
• hard (‘wooden’) subcutaneous tissue that is painful on palpation
• oedema beyond the margin of erythema
• cutaneous anaesthesia
• gas in the soft tissues (detected by palpation [skin or soft tissue crepitus] or imaging)
• systemic features, including fever, leucocytosis, elevated C-reactive protein (CRP), delirium or acute kidney impairment
• rapidly spreading infection.

Penetrating and crush injuries often lead to necrotising skin and soft tissue infection; necrotising infection can also follow surgical procedures. Life-threatening S. pyogenes necrotising fasciitis can occur spontaneously or follow varicella infection (chickenpox). Diabetes is also a risk factor for necrotising skin and soft tissue infection.