It's common for older adults to suffer from some form of arthritis, but children can often be stricken with the disease. Juvenile rheumatoid arthritis, or JRA (J-R-A), is classified separately from adults because the course of the disease in children is usually different than in adults. There are at least three main subsets of childhood arthritis, each affecting different joints with a distinct pattern of symptoms. The three subsets are polyarticular (poly-are-TIK-you-lar) JRA, pauciarticular (paw-see-are-TIK-you-lar) JRA, and systemic-onset JRA. Polyarticular disease affects more than five joints and is the type that is most similar to adult rheumatoid arthritis. Girls are two times more likely to suffer from this disease than boys. Pauciarticular is a disease that affects a few joints like your knees, elbows, wrists, and ankles. This type of JRA is considered the most common and affects more than 50 percent of children with arthritis. Systemic-onset begins with generalized symptoms, particularly a fever, rash, inflammation, anemia, and enlarged lymph nodes. This type of JRA is the least common and affects only about 10 percent of children with arthritis. It disappears within a year in half of the children affected.