Rheumatoid arthritis. False-colour X-rays showing destruction of the toe joints in both feet due to rheumatoid arthritis. The joints of the big toes are particularly affected. Rheumatoid arthritis is a severe type of inflammatory joint disease in which the body's immune system turns against itself (autoimmune disease) and damages joints and surrounding soft tissues. The joints affected become extremely painful and progressively deformed. Treatment is based on drugs (non- steroidal & steroidal anti-inflammatory agents) or joint replacement in the most severe cases.