Rheumatoid arthritis (RA) is an autoimmune disease. It causes joint problems such as:

  • pain
  • swelling
  • stiffness
  • loss of function

According to Mayo Clinic, joint damage from RA is usually symmetrical. If a joint is affected on one side of the body, the same joint on the other side will probably be affected as well. This is one way that doctors distinguish RA from other forms of arthritis, such as osteoarthritis.