Still's Disease

Still’s disease is a rare type of arthritis that is thought to be autoummune or autoinflammatory. It has similar symptoms to systemic-onset juvenile idiopathic arthritis -- fever, rash and joint pain. It begins in adulthood, so it's compared to rheumatoid arthritis. Inflammation may affect a few joints at first. Over time, more joints may be involved. Some people may have only one bout of the illness followed by lasting remission (no visible symptoms), while others develop chronic arthritis. The disease affects men and women equally, usually young adults between the ages of 16 and 35. This rare type of inflammatory arthritis is marked by fever, rash and joint pain.

Source: Arthritis Foundation