Adult Still's disease. A new consideration in pyrexia of unknown origin.

Adult Still's disease is a recently recognised syndrome which is an important and often unrecognised cause of pyrexia of unknown origin. A knowledge of the clinical features of this disease may save patients with undiagnosed fever from prolonged and invasive investigations. The condition usually responds to conservative therapy with non-steroidal anti-inflammatory agents and bed rest, although in a minority of patients more toxic drugs may be required. The prognosis is usually good although long-term follow-up studies of these patients are small in number, and the most recent review sounds a warning as to the incidence of chronicity. Sufficient evidence now exists to identify Still's disease as a separate nosological entity in adults. It should be added to the ever-expanding list of causes of pyrexia of unknown origin.