Childhood arthritis
Childhood arthritis (also known as juvenile arthritis, JRA, Juvenile Idiopathic Disease or Arthritis, or Stills Disease) is any form of chronic arthritis or chronic arthritis-related conditions which affects individuals under the age of 16. Most types are autoimmune disorders.

Signs and symptoms
Several types of childhood arthritis exist, the most common being juvenile idiopathic arthritis (JIA), also known as juvenile rheumatoid arthritis (JRA) or juvenile chronic arthritis (JCA).  Other types of childhood arthritis include juvenile myositis, juvenile lupus, juvenile scleroderma, vasculitis, and fibromyalgia.JRA again can be divided into three main forms: The classification is based upon symptoms, number of joints involved and the presence of certain antibodies in the blood.
Polyarticular arthritis is the first type of arthritis, which affects about 30–40% of children with arthritis and is more common in girls than boys. Typically five or more joints are affected (usually smaller joints such as the hands and feet but many also affect the hips, neck, shoulders and jaw).
Oligoarticular (aka pauciarticular) arthritis can be early or late onset and is the second type of arthritis, affecting about 50% of children with juvenile arthritis. This type affects fewer than four joints (usually the large joints such as knees, ankles or wrists) and may cause eye inflammation in girls with positive anti-nuclear antibodies (ANA). Girls younger than eight are more likely to develop this type of arthritis.
Systemic disease is the least common form, with 10–20% of children (boys and girls equally) being affected with limited movement, swelling and pain in at least one joint. A common symptom of this type is a high, spiking fever of 103 °F (39.4 °C) or higher, lasting for weeks or months, and a rash of pale red spots on the chest, thighs or other parts of the body may be visible.

Cause
In most cases, juvenile arthritis is caused by the body attacking its own healthy cells and tissues, i.e. autoimmunity, causing the joint to become inflamed and stiff. Once the joint has become inflamed and stiff, damage is done to the joint and the growth of the joint may by changed or impaired. The underlying cause in the malfuction of the autoimmune system is unknown; dietary habits and emotional state seem to have no effect on the disease.

Diagnosis
Early diagnosis and treatment by a paediatric rheumatologist or a rheumatologist can help manage inflammation, relieve pain, and prevent joint damage. However, it is difficult for doctors to diagnose the disease. Careful examination, laboratory tests (blood and urine), and various forms of imaging like X-rays may be some of the tests conducted by a doctor. Doctors may perform some of the following tests to diagnose the condition
ANA (Antinuclear Antibody) Test
Joint Aspiration
Rheumatoid Factor (RF) Test

Treatment
The treatment of juvenile arthritis includes medications, physical therapy, splints and in severe cases surgery. Methotrexate is commonly prescribed to children with juvenile arthritis. These treatments are focused on reducing swelling, relieving pain and maintaining full movement of joints. Children are encouraged to be involved in extra-curricular activities, physical activity when possible, and to live a "normal" life.

Epidemiology
In the US it affects about 250,000-294,000 children making it one of the most common childhood diseases.

References
External links

National Institute of Arthritis and Musculoskeletal and Skin Diseases - US National Institute of Arthritis and Musculoskeletal and Skin Diseases