Polyarticular juvenile rheumatoid arthritis (JRA), also known as polyarthritis, affects five or more joints during the first 6 months of symptoms. This type of JRA is more severe than pauciarticular JRA (oligoarthritis) because it affects more joints and tends to get worse over time.

Polyarticular JRA often begins in large joints, such as the knee or hip, but may start in the small joints of the hands and fingers. It also may affect the knees, ankles, feet, neck, and jaw.

Symptoms of polyarticular JRA usually affect the same joints on both sides of the body, such as the joints of both hands. A child with polyarthritis may also develop:

• Joint damage (erosion).
• Whole-body (systemic) symptoms, such as weakness, fever, and rash.
• Small bumps under the skin (rheumatoid nodules), especially at pressure points such as the elbows or heels.