Achy, painful joints are typically something we associate with aging. But for children with juvenile arthritis, these symptoms can occur as early as 1 or 2 years of age.
Most types of juvenile arthritis are known as autoimmune disorders, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). In a healthy body, the immune system fights off bacteria and viruses. But with an autoimmune disorder, the body mistakenly attacks some of its own healthy tissues and cells. These attacks cause inflammation, redness, pain, swelling, and warmth in the joints. And eventually, the inflammation can damage the joints.
Most children who develop arthritis are born with certain genes that make them susceptible to joint inflammation, says Robert Colbert, MD, PhD, chief of the pediatric translational research branch of NIAMS in Bethesda, Md. Juvenile arthritis, which refers to arthritis that strikes children under age 18, is one of the most common childhood diseases in the United States, according to the Arthritis Foundation. About 294,000 children receive a juvenile arthritis diagnosis each year.
The disease is a bit different from arthritis in adults. Because children are still growing and developing, arthritis can have a different effect on their joints, Dr. Colbert says. And while some children with juvenile arthritis don’t carry the disease into adulthood, about one-third to one-half of them still have it 10 years after the disease is first diagnosed.
Juvenile Arthritis Types That Affect Children
Medical experts have pinpointed several different types of juvenile arthritis. These include:
- Polyarticular juvenile arthritis. This is the type of arthritis children have when they have symptoms in five or more joints — “poly” means many — in the first six months of the disease. About 30 percent of all juvenile arthritis cases are found to be this type. Children with polyarticular juvenile arthritis may also have a positive blood test for a protein called rheumatoid factor; if this is the case, they may have a more severe and permanent form of the disease. This kind of arthritis usually involves small joints. “In addition to knees and ankles, typically the wrists and hands are involved,” Colbert says. It’s more common in girls and is usually more severe than oligoarthritis.
- Monoarthritis/oligoarthritis (pauciarticular) juvenile arthritis. The prefix “mono” is used when one joint is involved, and “oligo” refers to a few joints, generally four or fewer. About 50 percent of all juvenile arthritis cases are this type. This kind of arthritis tends to be diagnosed between ages one to five, or during adolescence, Hollister says. It is often seen in larger joints, such as the knee or ankle, and is sometimes accompanied by eye symptoms. Children with this type of arthritis are more prone to developing uveitis, or inflammation in the eye. A child who has been diagnosed with oligoarthritis should be seen by an ophthalmologist to be monitored for uveitis.
- Systemic juvenile arthritis. This type comprises about 10 percent of all cases of juvenile arthritis. Both the joints and some internal organs, such as the heart and lungs, can become inflamed as a result of systemic juvenile arthritis. “Those children have high spiking fevers, and most will have a rash,” Colbert says. Fevers associated with this type of arthritis, which can climb to 103 degrees Fahrenheit or higher once or twice a day, may last for weeks or months, sometimes even before the joints become swollen and painful. The child may also have swollen lymph nodes, an enlarged liver or spleen, and inflammation in the lining of the heart or lungs, which can usually be seen on X-ray. Sometimes a special study of the heart, an echocardiogram, is performed to get a more detailed picture. The good news here: When children with this form of arthritis are treated, there’s no long-term damage to their heart or lungs, Colbert says.
- Psoriatic juvenile arthritis. When arthritis occurs in children with psoriasis (a skin rash that appears as red, scaly plaques), it’s called psoriatic juvenile arthritis. Psoriatic arthritis may also cause a finger or toe to become inflamed and swollen. It’s also associated with pitting or splitting of the nails.
- Enthesitis-related arthritis. This form of childhood arthritis is associated with inflammation where tendons (fibrous tissue that attaches muscle to bone) and ligaments (fibrous tissue that attaches bone to bone) attach to bone, typically around the knee or the Achilles tendon on the back of the ankle. Some children may also experience pain and stiffness in the lower back and develop something called spondyloarthritis or ankylosing spondylitis, which causes inflammation in the spine, including the pelvis and hips, as well as the knees and ankles. Inflammation can also occur in the eyes, skin, or bowels.
Juvenile Arthritis Symptoms to Know About
“Many children appear to experience arthritis differently from adults and don’t complain of pain,” Colbert says. So it’s important to look for other signs that your child may be experiencing juvenile arthritis, such as:
- Walking with a limp or having trouble going up or down stairs
- Difficulty throwing a ball or opening a door
- Swollen, warm joints
- A high fever without any apparent cause
- Swollen lymph nodes
- Skin rash
Staying alert to symptoms like these and reporting them to your child’s doctor will help you to get an early diagnosis and treatment, which can help minimize the effects of painful joints.