Juvenile rheumatoid arthritis (JRA) is a term used to describe a common type of arthritis in children. It is a long-term (chronic) disease resulting in joint pain and swelling.

The cause of JRA is not known. It is thought to be an autoimmune illness. In this type of condition, the body's immune system mistakenly attacks and destroys healthy body tissue.

JRA usually occurs before age 16.

It is divided into several categories:

• Systemic JRA involves joint swelling or pain, fevers, and rash. It is the least common category.
• Polyarticular JRA involves many joints. This form of JRA may turn into rheumatoid arthritis. It may involve large and small joints of the legs and arms, as well as the TMJ and cervical spine.
• Pauciarticular JRA involves only a few joints, usually the hips, knees, or ankles.

Many other medical problems can cause symptoms similar to those of juvenile rheumatoid arthritis, including:

• Lyme disease, rheumatic fever, bone infections (osteomyelitis), and other infections
• Sarcoidosis, psoriatic arthritis, vasculitis
• Inflammatory bowel disease