Childhood Arthritis (JA) also known as Juvenile arthritis is any form of arthritis or arthritis related conditions which affects individuals under the age of 16. Juvenile Arthritis is a chronic, autoimmune disease affecting approximately 294 000-250 000 children and teens making juvenile arthritis one of the most common childhood diseases in the US. Three classifications of juvenile arthritis exist-juvenile rheumatoid arthritis (JRA), juvenile chronic arthritis (JCA), and juvenile idiopathic arthritis (JIA), of which juvenile rheumatoid arthritis is the most common.
Three main types of juvenile rheumatoid arthritis exit and classification is based upon symptoms, number of joints involved and the presence of antibodies in the blood. Polyarticular arthritis is the first type of arthritis which affects about 30-40% of children and is more common in girls than boys.