Topic Overview

What is juvenile idiopathic arthritis?

Juvenile idiopathic arthritis (JIA) is a childhood disease that causes inflamed, swollen joints. This makes joints stiff and painful. The term "juvenile idiopathic arthritis" is replacing the American "juvenile rheumatoid arthritis" and the European "juvenile chronic arthritis."

Some children with the disease grow out of it after they get treatment. Others will need ongoing treatment as adults.

There are several types of juvenile idiopathic arthritis.

• Oligoarticular (formerly known as pauciarticular) is the most common and often the mildest type. Your child may have pain in 1 to 4 joints during the first 6 months of the disease, such as the knees, ankles, fingers, toes, wrists, elbows, or hips. The condition is called persistent oligoarthritis if no more than 4 joints are involved, and extended oligoarthritis if more joints become involved in the first 6 months.
• Polyarticular affects more joints and tends to get worse over time. It is further divided by whether or not the child has an antibody called rheumatoid factor in their blood. If the antibody is present, the condition is more severe, and is more like rheumatoid arthritis in adults.
• Systemic is less common, but it can be the most serious. It causes pain in many joints and can also spread to organs.
• Enthesitis-related is also less common than oligoarticular and polyarticular JIA. It most often affects the areas where tendons and ligaments attach to bones (the enthesis). The joints may also be affected.
• Psoriatic usually combines joint tenderness and inflammation (arthritis) with psoriasis of the skin or a related condition of the nails.

What causes juvenile idiopathic arthritis?

Doctors don't really know what causes the disease. But there are a number of things that they think can lead to it. These things include:

• An immune system that is too active and attacks joint tissues.
• Viruses or other infections that cause the immune system to attack joint tissues.
• Having certain genes that make the immune system more likely to attack joint tissues.

What are the symptoms?

Children can have one or many symptoms, such as:

• Joint pain.
• Joint swelling.
• Joint stiffness.
• Trouble sleeping.
• Problems walking.
• Fever.
• Rash.

In some cases these symptoms can be mild and hard for you to see. A young child may be more cranky than normal or may go back to crawling after he or she has started walking. You may notice that your child feels stiff in the morning or has trouble walking.