Rheumatoid arthritis (RA) is an autoimmune disorder that primarily affects the joints. In RA, the immune system mistakenly attacks the synovium, the lining of the membranes that surround the joints.

This causes inflammation that can lead to joint damage, pain, swelling, stiffness, and loss of function. RA commonly affects joints in the hands, wrists, and knees symmetrically, meaning both sides of the body are usually affected equally. It can also affect other organs and systems in the body. Treatment typically involves medication to reduce inflammation and pain, physical therapy, and sometimes surgery in advanced cases.

Early diagnosis and treatment can help manage symptoms and prevent joint damage.