ST. LOUIS, July 18, 2011 /PRNewswire/ -- Arthritis does not discriminate by age, a little-known fact for many parents. While most of us think of arthritis as a condition that affects older people only, nearly 300,000 American children develop the disease, which is often known as juvenile rheumatoid arthritis. Childhood arthritis can affect kids from six months to 16 years old, according to KidsHealth.org. Symptoms of childhood arthritis include swollen joints that stay inflamed for weeks. Children may feel stiffness in their neck or hips, or have a morning limp. Rashes may suddenly appear and disappear. High fevers may spike in the evening and then suddenly disappear. In some cases, eye inflammation can occur. Proper nutrition can also become an issue with this disease. "Children with arthritis may lose their appetite due to joint pain or arthritis medication," said Dr. Carl W. Hastings, chief scientific officer of Reliv International, Inc. "Nutritional problems related to childhood arthritis can include weight loss and slow growth," he added. "Parents should consider a nutritional supplement made expressly for kids to ensure their children with arthritis get the proper nutrition they need. Reliv Now for Kids, for example, provides a broad base of essential vitamins, minerals and micronutrients necessary to keep growing bodies healthy," Dr. Hastings said. Your pediatrician may diagnose juvenile rheumatoid arthritis or send you to a pediatric rheumatologist for diagnosis, because it is a difficult disease to diagnose. Doctors don't know the cause of the juvenile rheumatoid arthritis. Researchers have discovered no single test for diagnosing this condition, and symptoms vary from child to child. Part of the problem is that juvenile arthritis isn't a single disease. Instead, it's an umbrella term that describes the symptoms of most children with chronic arthritis of unknown cause, according to Dr. Thomas A. J. Lehman of the Hospital for Special Surgery in New York. Parents should watch their children for prolonged swollen and painful joints, or morning stiffness that may cause a limp for six weeks or more. If they see these signs, they should contact their pediatrician.