Adult-onset Still's disease in a patient over 80 years old successfully treated with low-dose methotrexate therapy.

We report on an 83-year-old Japanese woman with adult-onset Still's disease (AOSD), with marked hypercytokinemia (serum levels of ferritin (Fer) and interleukin (IL)-18 were markedly high). On seeing older patients with fever of unknown origin (FUO), particularly Asians, AOSD should be considered. Reduced doses of oral prednisolone following intravenous methylprednisolone (mPSL) therapy caused a flare-up of AOSD and led to Pneumocystis carinii (jeroveci) pneumonia.