What is juvenile idiopathic arthritis? What can it mean for you and your child?

Juvenile idiopathic arthritis (JIA) is an autoimmune disease.

Polyarticular JIA affects 5 or more joints—often the same joints on both sides of the body. Sometimes the neck, jaw joints, and small joints in the hands and feet are affected.

  • JIA is the most common type of arthritis in children
  • It occurs more often in girls
  • It can cause inflammation, swelling, stiffness, and pain in the joints, as well as other symptoms, depending on the type of juvenile idiopathic arthritis a child has

What should you know about JIA?

A mom and her daughter at the doctor's office.
  • It usually develops before age 16
  • It affects every child differently
  • Symptoms can vary daily, even in the same child
  • It can be mild and short term—or it can be severe and cause permanent damage to joints

Getting the proper diagnosis and treatment is important. It can reduce the signs and symptoms of juvenile idiopathic arthritis.

What causes juvenile idiopathic arthritis?

The word "idiopathic" means "the cause is unknown." But even though scientists and doctors don't know the exact cause of JIA, they do know that it's likely caused by a combination of factors:

  • Genetics
  • Environment
  • Immune system


Some children with JIA produce too much of certain proteins, including tumor necrosis factor (TNF).

When too much of certain proteins, such as TNF, are produced, inflammation can result. This can contribute to symptoms of JIA such as joint pain, swelling, and stiffness.