If your child has joint pain or swelling that won't go away, it could be JRA. Here's what you need to know about the many types of juvenile arthritis.

Juvenile idiopathic arthritis, more commonly known as juvenile rheumatoid arthritis or JRA, is the most common form of arthritis in children.

JRA causes inflammation in the joints that can lead to debilitating joint damage. 

The cause of JRA isn’t known, but it’s thought that the body’s immune system mistakenly attacks cells in the joints as if they were bacteria or a virus. 

Juvenile arthritis affects one of every 1,000 children. In the United States, about 300,000 kids have been diagnosed with rheumatoid arthritis.

The good news is that with proper treatment, most children can still lead normal, happy, and active lives.

Is it JRA?

How can you know whether your child’s joint pain is JRA or normal childhood aches and pains?

With JRA, most children have morning joint stiffness that gets better as the day goes on, explains Sampath Prahalad, MD, Marcus professor of rheumatology, chief of the division of pediatric rheumatology, and associate professor of pediatrics and human genetics at Emory University School of Medicine in Atlanta.

Children with growing pains or activity-related aches usually complain of joint pain later in the day, not first thing in the morning.

Also, kids with JRA don’t complain of joint pain but rather swelling, and they also say that their joints can’t fully move as they should, adds Dr. Prahalad.

Getting the Right Diagnosis

If your child has experienced morning joint stiffness and swelling for six weeks or longer, it could be juvenile RA.

It’s important to get a correct diagnosis and start rheumatoid arthritis treatment as soon as possible because untreated arthritis can cause permanent joint damage and loss of cartilage.

Prahalad notes that growth problems can also occur. “For instance, one knee could grow longer than the other,” he says.

There is no one test that can confirm a diagnosis of JRA, but rather history, physical examination, blood tests, and X-rays all contribute to a picture that is consistent with the disease.

In general, symptoms of JRA can get better and disappear on their own. This is called remission, and they can also come back and get worse, which is called a flare. Discuss symptoms and the pattern of pain with your child’s doctor.

Types of Juvenile Rheumatoid Arthritis

The most common type of juvenile arthritis is called oligoarthritis, says Prahalad.

It can affect up to four joints during the first six months of the disease. It's usually found in children younger than 6 years and is two to three times more common in girls, he adds.

Juvenile RA can also cause inflammation in the eyes, so children should be followed closely by an eye doctor.

Others types of juvenile arthritis include: 

• Polyarticular arthritis-rheumatoid factor negative: arthritis in five or more joints during the first six months of disease without rheumatoid factor, an antibody produced in some people with rheumatoid arthritis.
• Polyarticular arthritis-rheumatoid factor positive: arthritis in five or more joints during the first six months of disease with rheumatoid factor.
• Psoriatic arthritis: a combination of arthritis and the skin condition psoriasis.
• Enthesitis-related arthritis: arthritis and inflammation at the point where a ligament, tendon, or joint capsule attaches to the bone (for example, around the knee or ankle).
• Systemic arthritis: JRA that affects the entire body and can make a child feel very sick; symptoms include a high fever and rash, and many joints may eventually become swollen, painful, and stiff.
• Undifferentiated arthritis: arthritis that doesn’t fit any criteria. 

Treating JRA

Doctors have a much bigger arsenal of new medications to use for rheumatoid arthritis than they had in the past.

These include prescription-strength anti-inflammatory drugs, steroid injections, disease-modifying anti-rheumatic drugs (DMARDs) like methotrexate (Trexall, Rheumatrex), and biologic agents such as entanercept (Enbrel). 

With aggressive early treatment many children will be able to outgrow their JRA. Remission also depends on what type of arthritis a child has. For instance, Prahalad says, kids with rheumatoid factor-positive arthritis usually go on to have the disease into adulthood.

But overall, he says, advances in the field over the last two decades have made the future brighter for children with JRA: “At arthritis summer camps 20 years ago, you might see children in wheelchairs. Today, that’s rare to see.”