Rheumatoid arthritis (RA) is an autoimmune condition that involves joint inflammation and pain. Although less common than osteoarthritis, RA is more debilitating and usually starts earlier, between the ages of 30 and 50.

About 1.3 million Americans, at least two-thirds of them women, have RA, according to the Centers for Disease Control and Prevention (CDC).

The cause of RA is not entirely understood. It begins with an altered immune response, in which immune cells attack normal cells in the joints. This causes inflammation and pain in the joints, frequently in the same joint on both sides of the body. RA can also affect the eyes, heart and other organs.

RA may begin as pain, swelling or stiffness in a few joints. The progress of the disease varies. It may remain the same for many years or progress to other joints and systems in the body. The swelling can deform the bones and tendons in the joints, which may make the joints difficult to use. Some people eventually lose the ability to work or perform daily tasks.

Physicians may use multiple blood tests and a physical examination to diagnose RA. Guidelines to classify the disease include joint pain or swelling in multiple joints for more than six weeks.

There is no known cure for RA. Treatment concentrates on pain relief and slowing the progression of the disease.

Great strides have been made in recent years with drugs that can slow RA’s progress. Drug treatment may include basic pain relievers such as acetaminophen or anti-inflammatory drugs. Other drugs modify the disease's progress or work on parts of the immune system that malfunction to trigger RA. The course of RA is different for each patient and different drug combinations may provide relief. No drugs can reverse damage inflicted on the joints.

Some surgical procedures can remove parts of damaged joints or even replace a joint (arthroplasty).

Research into the causes and progress of RA continues. Scientists are studying genetics and the biochemistry of the immune system. Other studies focus on potential new drugs, drug combinations or other treatment methods.