What are the signs and symptoms of the disease?

Children with JRA have joint inflammation and stiffness. The inflammation makes the joints red, warm, sore, and swollen. Some children with JRA have joint pain, while many do not. There are three kinds of JRA, each with its own characteristic symptoms.

About half the children with JRA have a pauciarticular form of the disease. This type involves four or fewer joints. It usually involves large joints, such as the knees. Twenty to 30% of the children with this form of JRA have eye disease. They may have iritis, which is inflammation of the colored part of the eye. Some have uveitis, which involves the inner eye.

The polyarticular form of JRA is found in about 1/3 of the children with JRA. This form involves five or more joints. It usually involves small joints, such as those in the hands and feet. It often involves the same joints on either side of the body. For example, it may involve the large joint of each thumb. Some children with polyarticular JRA have a special antibody called IgM rheumatoid factor. These children have a more severe form of JRA, similar to adult rheumatoid arthritis.

About 20% of the children with JRA have a systemic, or bodywide, form of the disease. This is also known as Still's disease. It causes joint inflammation and stiffness. In addition, the child may have a fever and light pink rash. Still's disease may also affect the heart, liver, spleen, and lymph nodes.