[Adult onset Still's disease as a diagnostics challenge in case of fever of unknown origin].

Fever of unknown origin is often a diagnostic challenge. Here we present a case of 55-year-old woman with a history of a few months fever, progressing weakness and salmon-coloured, macular skin rash. The differential diagnosis included neoplasmatic conditions, infections and connective tissue disorders. Finally adult onset Still's disease was suspected. Glucocorticosteroid treatment was induced. During the therapy a central nervous system infection occurred, which was fatal for the patient. The presented clinical case shows that among many causes of fever of unknown origin, adult onset Still's disease should be taken into account.