Article: Juvenile arthritis

Juvenile Rheumatoid Arthritis (JRA) is the most common form of arthritis in children. Typical symptoms of JRA are joint inflammation, joint contracture (stiff, bent joint), joint damage and/or change in growth. Other symptoms include joint stiffness or decreased activity level. Children with JRA vary in the degree to which they are affected by particular symptoms.

The 3 major types of JRA are pauciarticular JRA (affecting 4 or fewer joints), polyarticular JRA (affecting 5 or more joints) and and systemic JRA (affecting at least one joint and causing inflammation of internal organs).

JRA can occur in boys or girls of any age, but symptoms most commonly begin during the toddler or early teenage years. Juvenile rheumatoid arthritis affects an estimated 30,000 to 50,000 children in the United States. Of these children, 50 percent have pauciarticular JRA, 40 percent have polyarticular JRA and 10 percent have systemic onset JRA. No one knows what causes JRA. Theories include both genetic and environmental factors.