Rheumatoid arthritis is a chronic inflammatory disease that can affect more than joints. In some people, the disease can damage several body systems, including the skin, eyes, lungs, heart, and blood vessels. An autoimmune disease, rheumatoid arthritis occurs when the immune system mistakenly attacks the tissues of its own body. Unlike osteoarthritis wear, rheumatoid arthritis affects the coating of the joints, which causes painful inflammation that can eventually lead to bone erosion and deformity of the joints. Inflammation associated with rheumatoid arthritis can also damage other parts of the body.