Necrotising fasciitis is a rare condition that should be diagnosed early and managed aggressively in order to avoid death. We present a case of necrotising fasciitis of the thumb and discuss the assessment and management of this serious condition. A 44-year-old woman presented with a painful and erythematous right thumb and progressive swelling of her hand following a minor injury to the tip of her thumb 3 days previously. A diagnosis of necrotising fasciitis was made and the patient underwent urgent debridement of non-viable tissue. She required 1 week of supportive therapy in intensive treatment unit and was discharged from hospital after 3 weeks. Necrotising fasciitis is a rapidly progressing life-threatening infection, usually caused by streptococcal organisms. Immediate resuscitation, broad-spectrum intravenous antibiotics and early surgical debridement are necessary in order to avoid significant morbidity and mortality.