Rheumatoid Arthritis Overview
Rheumatoid arthritis (RA) happens when your body’s defenses – your immune system – targets your joint linings. RA affects joints on both sides of the body, such as both hands, both wrists, or both knees. This symmetry helps to set it apart from other types of arthritis. It can also affect the skin, eyes, lungs, heart, blood, or nerves.