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Juvenile Idiopathic Arthritis (JIA)

Medically reviewed by: AnneMarie C. Brescia, MD

What Is Juvenile Idiopathic Arthritis?

Juvenile idiopathic arthritis (JIA) is a group of disorders that cause arthritis (stiff, swollen, painful joints) in children. Some types are also called juvenile rheumatoid arthritis (JRA).

Depending on the type of JIA, a child may also have problems with the eyes, skin, heart, lungs, and intestines (bowels).

Treatments can help with symptoms so children with JIA can live a full and active life. The symptoms can go away for a time (called remission). In some kids, the condition goes away permanently.

What Are the Types of Juvenile Idiopathic Arthritis?

The types of JIA and their symptoms are:

Systemic JIA

Children with systemic JIA have arthritis in 1 or more joints. They also have a fever and rash that come and go. They may have swollen and problems with the heart, lungs, and blood.

Polyarticular JIA

A child with polyarticular JIA has arthritis in 5 or more joints in the first 6 months of disease. They also might have inflammation inside the eye (called uveitis) and other problems.

Oligoarticular JIA

Children with oligoarticular JIA have arthritis in fewer than 5 joints in the first 6 months of the disease. In some children, more joints become affected after that. They may also have .

Enthesitis-Related JIA

Children with enthesitis-related JIA have enthesitis (inflammation where tendons and ligaments connect to bone) and arthritis. They may also have uveitis and inflammatory bowel disease (IBD).

Psoriatic JIA

Psoriatic JIA affects children who also have psoriasis (a skin disorder where thick, red plaques grow on the skin) or a close relative with psoriasis. They may also have uveitis, swelling of fingers and toes, and changes in their nails.

Undifferentiated JIA

Undifferentiated JIA is when someone's symptoms don’t fit into any of the above types or fall into more than one of those types.

What Causes Juvenile Idiopathic Arthritis?

JIA is an autoimmune disease. This means that the body’s immune system, which normally attacks germs, mistakenly attacks the joints. This causes inflammation (swelling and irritation) in the joints and other problems.

Doctors don’t know exactly why kids and teens get JIA. “Idiopathic” means “from an unknown cause.” It can run in families but often does not. It’s likely due to a combination of:

  • genetic (inherited) causes 
  • the way the immune system responds to infection and illness
  • a trigger such as an infection

How Is Juvenile Idiopathic Arthritis Diagnosed?

To diagnose the different types of JIA, doctors:

  • ask about symptoms
  • do an exam
  • ask whether other family members have had similar problems
  • do X-rays or other imaging studies to look inside the joints
  • order blood tests to check for:
    • anemia or other blood problems
    • inflammation in the body
    • markers for some types of arthritis or autoimmune illnesses

Sometimes, an orthopedic surgeon (bone doctor) takes samples of joint fluid or synovium (the lining of the joints). The sample is sent to the lab for testing.

How Is Juvenile Idiopathic Arthritis Treated?

Systemic JIA is treated by a care team that includes:

  • a rheumatologist (for problems with joints and connective tissue)
  • a primary care doctor (such as a pediatrician or family medicine doctor)
  • a physical therapist

Kids with uveitis also get care from an ophthalmologist (eye doctor). Treatment goals are to ease pain and inflammation, improve strength and flexibility, and prevent joint damage. Treatment usually includes medicines to ease inflammation and physical therapy.

Sometimes surgery is needed for damaged joints.

How Can Parents Help?

JIA is a lifelong disease, but treatments can help ease pain, keep kids active, and prevent long-term joint damage. To help your child:

  • Make sure your child takes all medicines exactly as directed.
  • Work with your child’s physical therapist to develop a regular exercise program. This will help keep your child’s muscles strong and flexible.
  • Learn about JIA with your child. Your care team is a great resource. You can also find information and support online at:
Medically reviewed by: AnneMarie C. Brescia, MD
Date reviewed: August 2021