Kawasaki disease (KD) is an acute vasculitis characterized by marked tropism of the coronary vessels. Usually a childhood disease, KD can occasionally be observed in adults. We report a case of adult-onset KD that presented as a prolonged fever of unknown origin with subsequent development of severe vasculitis, manifested by coronary aneurysms and peripheral gangrene of the lower limbs. Therapy with intravenous immunoglobulins, corticosteroids, aspirin, anticoagulants, and prostacyclin analogue resulted in rapid improvement in the patient's condition but he required partial distal amputation for irreversible gangrene. Peripheral ischaemia leading to gangrene is a very rare feature of KD vasculitis with only 19 cases previously published in the Medline-indexed literature. The outcomes of those patients were poor, being either fatal or requiring distal amputation. All prior cases affected young children less than 1 year old and, to the best of our knowledge, the present case is the first description of peripheral gangrene in adult-onset KD.