Rheumatoid arthritis (RA) is a disease of the immune system. It causes inflammation and swelling not only in your joints but also throughout the body. This means the body’s defense system attacks the body's normal cells as foreign and damages them as it would an invader like a virus. In RA, the tissue that lines the inside of joints is affected most often. The joints in your hands, wrists, and knees can become swollen, deformed, and often painful. Symptoms are often symmetrical. This means if the joint in your left pinky finger is affected, the joint in your right pinky finger may also be affected.

If RA is not treated, the swelling, deformity, and pain can worsen, which can cause damage to your joints. Even though RA usually affects joints, it can also cause problems for other parts of your body:

  • Heart
  • Lungs
  • Blood vessels
  • Eyes
  • Skin

If you think you have RA, talk to your doctor about what you are feeling.