Juvenile idiopathic arthritis, formerly known as juvenile rheumatoid arthritis, is the most common type of arthritis in children under the age of 16.

Juvenile idiopathic arthritis can cause persistent joint pain, swelling and stiffness. Some children may experience symptoms for only a few months, while others have symptoms for many years.

Some types of juvenile idiopathic arthritis can cause serious complications, such as growth problems, joint damage and eye inflammation. Treatment focuses on controlling pain and inflammation, improving function, and preventing damage.

Symptoms

The most common signs and symptoms of juvenile idiopathic arthritis are:

• Pain. While your child might not complain of joint pain, you may notice that he or she limps — especially first thing in the morning or after a nap.
• Swelling. Joint swelling is common but is often first noticed in larger joints such as the knee.
• Stiffness. You might notice that your child appears clumsier than usual, particularly in the morning or after naps.
• Fever, swollen lymph nodes and rash. In some cases, high fever, swollen lymph nodes or a rash on the trunk may occur — which is usually worse in the evenings.

Juvenile idiopathic arthritis can affect one joint or many. There are several different subtypes of juvenile idiopathic arthritis, but the main ones are systemic, oligoarticular and polyarticular. Which type your child has depends on symptoms, the number of joints affected, and if a fever and rashes are prominent features.

Like other forms of arthritis, juvenile idiopathic arthritis is characterized by times when symptoms flare up and times when symptoms may be minimal.

When to see a doctor

Take your child to the doctor if he or she has joint pain, swelling or stiffness for more than a week — especially if he or she also has a fever.

Causes

Juvenile idiopathic arthritis occurs when the body’s immune system attacks its own cells and tissues. It’s not known why this happens, but both heredity and environment seem to play a role.

Risk factors

Some forms of juvenile idiopathic arthritis are more common in girls.

Complications

Several serious complications can result from juvenile idiopathic arthritis. But keeping a careful watch on your child’s condition and seeking appropriate medical attention can greatly reduce the risk of these complications:

• Eye problems. Some forms can cause eye inflammation. If this condition is left untreated, it may result in cataracts, glaucoma and even blindness.
• Eye inflammation frequently occurs without symptoms, so it’s important for children with this condition to be examined regularly by an ophthalmologist.
• Growth problems. Juvenile idiopathic arthritis can interfere with your child’s growth and bone development. Some medications used for treatment, mainly corticosteroids, also can inhibit growth.