A case of necrotising fasciitis in a patient receiving infliximab, an antitumour necrosis factor alpha (TNF-α) agent for rheumatoid arthritis, is presented. A widespread confluent, erythematous, pustular skin rash was the presenting sign. There was no fever throughout this admission. β-Haemolytic group A streptococcus was isolated from blood cultures and skin swabs. The adductor muscles and fascia around the site of a previous hip arthroplasty were necrotic on exploration. The case highlights the risk of severe sepsis in patients on anti-TNF-α treatment.