Children sometimes complain about aches in their joints. A joint is where the ends of bones meet, such as the knee joint, shoulder joint, or the small joints in the fingers and toes. Joint pain in children can be caused by a variety of things. But if a child's joints are swollen for 6 weeks in a row or longer, he or she may have juvenile arthritis (JA).
Juvenile arthritis is a long-lasting, chronic disease. It is the most common form of arthritis in children. In the United States, it affects nearly 250,000 children under the age of 16 years.
There are several types of juvenile arthritis. Nearly all of them are different from rheumatoid arthritis in adults. This is why the term "juvenile rheumatoid arthritis (JRA)" is no longer widely used.