Adult Still’s disease is a rare disease. Its symptoms include fever, joint pain and swelling, rashes etc. The cause of this disease is unknown. Research is being carried out taking into considerations several possibilities. Fever, rash and joint pain associated with this condition suggest that an infectious agent could be the reason for this disease. So far, no specific pathogen has been implicated in this disease. The rubella virus, mumps, parainfluenza and other such viruses have been associated with Adult Still’s disease. Some researchers feel that Adult Still’s Disease is an autoimmune disorder while others believe that it is caused due to hypersensitivity of the immune system. The levels of immune system mediators like interleukins, cytokines etc are raised in patients with Adult Still’s Disease. This could explain the inflammation and fever associated with the disease. It is difficult to say whether hormones and genetics play a role in the Adult Still’s disease. It seems to affect both men and women. It is observed more frequently among Caucasians although it is also seen in Blacks, Latinos and Orientals too. It doesn’t seem to be inherited among members of a family. The fact that this is a rare disease and the subsequent lack of data makes it difficult to identify the exact cause of this condition.