The joints are usually affected symmetrically (on both sides) in polyarticular JRA. Often, the small joints of the hands are affected, as well as other joints. Low grade fever, weight loss, and anemia may occur, and in severe cases growth problems. Most children with polyarticular disease test negative for rheumatoid factor and their prognosis is usually good with treatment. Fewer of the children with polyartiular JRA test positive for rheumatoid factor and are at higher risk for chronic, progressive destruction of joints.
Primer on the Rheumatic Diseases. Arthritis Foundation. Thirteenth edition.