Rheumatoid arthritis (RA) is a chronic autoimmune disease in which your immune system mistakenly attacks the lining of your own joints. This attack triggers inflammation, leading to pain, swelling, and stiffness in the affected joints.
Rheumatoid arthritis damages the tissue that cushions the ends of bones within a joint. While rheumatoid arthritis can affect any joint, it typically starts in the small joints of the hands and feet. It affects joints on both sides of the body, such as both knees or both hands.Â
Beyond the joints, this disease can also affect other body systems, including the skin, eyes, lungs, heart, and blood vessels. The inflammation caused by this disease is what harms other parts of the body.