Juvenile rheumatoid arthritis (JRA) is a childhood disease that affects the joints. (It’s also called juvenile idiopathic arthritis, or JIA). It has several different types. “Systemic-onset juvenile rheumatoid arthritis” is the rarest form, accounting for just 10%-20% of all JRA cases.
The word "systemic" means that it affects the entire body. The condition causes high, spiking fevers, rash, and joint aches. It usually starts when a child is between 5 and 10 years old. It affects boys and girls equally.
You may also hear it called “Still's disease,” named after the English doctor Sir George F. Still, who first recognized the illness in children in the late 1800s.
No one really knows what causes it. Scientists believe it’s caused by a faulty immune response, which may be triggered by something else, such as stress, or a viral or bacterial infection.
The classic signs are a very high fever (102 F or higher) and a pale pink or salmon-colored rash, usually on the child's chest and thighs. It’s sometimes confused with a bacterial infection, but antibiotics don’t help.
The fever tends to spike several times during the day. It usually peaks at night and then improves in the morning. Children also have joint pain, swelling, or both. That can become more painful when their fever is high.
Symptoms come and go over days, weeks, or months. Children with a low fever seem to be fine. When it returns, the child will look and act sick. Children can have "good" days with few or no symptoms, and worse days with flare-ups of more severe symptoms.
The disease also can cause inflammation of the lining of the lung (pleuritis) or lining of the heart (pericarditis), swollen lymph nodes, and an enlarged spleen and liver. Children with the condition may grow more slowly than normal, too.