There is no single test for rheumatoid arthritis. Sometimes rheumatoid arthritis can cause bumps called nodules to form over the elbows, knuckles, spine, and lower leg bones. See a picture of the most commonly affected joints. The disease usually affects both sides of the body at the same time. The disease also runs in some families. This means that the body's natural defense system attacks the joints.
But rheumatoid arthritis is an autoimmune disease. The exact cause of rheumatoid arthritis is not known. Rheumatoid arthritis is 2 to 3 times more common in women than in men. Over time, this inflammation may destroy the joint tissues. Rheumatoid arthritis causes tissues lining the joints to become swollen, stiff, and painful.
