[Clinical thinking and decision making in practice. A young woman with fever, arthralgia and exanthema].

A 19-year-old woman was admitted because of high fever, rash, arthralgia and sore throat. On physical examination a diffuse skin rash was observed, leaving a facial mask unaffected. C-reactive protein and erythrocyte sedimentation rate were raised (114 mg/l and 26 mm in the first hour, respectively); white blood cell count was normal (6.2 x 10(9)/l) with an increased count of immature forms. An infective, metabolic or haematological cause was excluded. Serum ferritin turned out to be extremely elevated (4318 micrograms/l), so adult-onset Still's disease was diagnosed. The patient fulfilled the criteria of Cush et al. for adult-onset Still's disease. She was first treated with non-steroidal anti-inflammatory drugs (NSAIDs) and, at a later stage in the disease, with corticosteroids. All symptoms disappeared and blood test results normalised.