Juvenile rheumatoid arthritis (JRA) is a disease that affects children age 16 and younger. It causes inflamed, swollen, stiff, and often painful joints. JRA may affect one or more joints and can cause a generalized illness.

The cause of JRA is unknown. Most experts believe it may be caused by a combination of the following factors:

• An overly active immune system that inappropriately attacks joint tissues, as if they were a foreign substance. Viral or bacterial infections are a suspected trigger of the autoimmune process.
• Genetic factors that make a child's immune system more likely to react inappropriately

Symptoms of JRA include:

• Joint pain and swelling that may come and go but are most often persistent.
• Joint stiffness in the morning.
• Irritability, refusal to walk, or protection or guarding of a joint. You might notice your child limping or avoiding the use of a certain joint.
• Often unpredictable changes in symptoms, from periods with no symptoms (remission) to flare-ups.

A child with JRA will likely be treated with a combination of medicines and physical therapy. The goals of medical treatment are to reduce your child's joint pain and to prevent disability.

For more information, see the topic Juvenile Rheumatoid Arthritis.