The onset of Addison's disease usually occurs after age 18.
One set of 21 adult-onset Still's disease patients were divided into four types, according to clinical course patterns
 In rare cases, AOSD can cause life-threatening complications, including hemophagocytic lymphohistiocytosis, IVDC, fulminant hepatitis, or disabling conditions such as aseptic meningitis and sensorineural hearing loss

