context: Juvenile rheumatoid arthritis is a childhood condition that affects your joints. It's also called juvenile idiopathic arthritis, or JIA. It has several different types. Systemic-onset juvenile rheumatoid arthritis is the rarest form. The word "systemic" means that it affects the entire body. It causes high fevers, rash, and joint aches. It usually starts when a child is between 5 and 10 years old, and affects boys and girls equally. You may also hear it called Still's disease. No one knows exactly what causes it. Scientists believe it could be a faulty immune system that responds in the wrong way to something else, like stress, or a viral or bacterial infection. You can't prevent systemic-onset juvenile rheumatoid arthritis. It's believed to run in families though, so family medical history can give you a clue. A doctor needs to diagnose it and get your child on track with the medicine she needs to get better in a hurry. Signs include a very high fever (102 F or higher) and a pale pink or salmon-colored rash, usually on the 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. This may become more painful when their fever is high. Symptoms come and go over days, weeks, or months. Children with a low fever can seem to be fine. When it flares up, the child will look and act sick. Children can have good days with few or no symptoms, and worse days with flare-up symptoms. This condition may also cause inflammation of the lining of the lung, called pleuritis, or the lining of the heart, called pericarditis. It can cause swollen lymph nodes, and an enlarged spleen and liver. Children who have it may grow more slowly than normal. There is no single test for systemic-onset juvenile rheumatoid arthritis. Your child's doctor will do a physical examination and check on any symptoms. He will probably ask if the condition runs in the child's family. Tests help rule out other diseases, including bacterial or viral infections, and other forms of arthritis. Your child may get the following tests: Blood, urine, and joint fluid tests X-rays, MRIs, and other imaging tests The results may show: Low red blood cell count, or anemia High white blood cell count High platelet count, which are the cells in blood that help it clot Higher levels of C-reactive protein and erythrocyte sedimentation rate, which are signs in your child's blood of inflammation Doctors usually treat the condition with nonsteroidal anti-inflammatory drugs ( NSAIDs) such as celecoxib ( Celebrex), diclofenac ( Voltaren), ibuprofen ( Advil, Motrin), and naproxen ( Aleve, Naprosyn). These help relieve fever, pain, and joint inflammation. Corticosteroid medications like prednisone are also used. They lessen the immune response and help with inflammation. Biologics are medicines which come from natural, or biological, sources. Some of these, like anakinra ( Kineret) or tocilizumab ( Actemra), are also used to treat systemic-onset juvenile rheumatoid arthritis. Children with this condition should get plenty of rest, especially when they have symptoms. When they feel up to it, exercise can help keep their joints strong and working well. Physical therapy also helps. In many children with this condition, the fever and rash go away within a few months. How quickly they improve depends on how severe they are. In some people, the arthritis can last into adulthood and still need treatment.