The Types of JIA

Oligoarticular arthritis, in which one to four joints in the body are affectedPolyarticular arthritis, in which five or more joints are affectedSystemic arthritis, which covers the whole body and includes joints, skin, and internal organsJuvenile enthesitis-related arthritis (ERA), in which the joints of the lower body (such as the ankle) and the spine are affected, according to KidsHealth.orgPsoriatic arthritis, which affects the joints and comes with a skin rash, per the Arthritis FoundationUndifferentiated, which isn’t clearly linked to one type of JIA

Signs and Symptoms of Juvenile Idiopathic Arthritis

The most common symptom of JIA is joint pain, with or without swelling, that develops over time and occurs along with joint stiffness after prolonged rest, such as when you first get up in the morning, says Yukiko Kimura, MD, chief of the division of pediatric rheumatology at the Joseph M. Sanzari Children’s Hospital in Hackensack, New Jersey, and a professor of pediatrics at Hackensack Meridian School of Medicine in Nutley, New Jersey. Stiffness “can last for a few minutes or for hours,” says Dr. Kimura. “In small children and babies, it might just cause them to be cranky and want to be picked up first thing in the morning, when previously they would get out of their crib about start crawling or walking. This stiffness typically gets better gradually as the day goes on.”

Signs and Symptoms of Oligoarticular JIA

According to KidsHealth.org, kids who develop arthritis in one to four joints in the first six months after diagnosis have oligoartiucular JIA. They can develop more joint arthritis as the disease progresses. Most typically, arthritis appears in what are known as the large joints:  knees, ankles, wrists, and elbows. Other symptoms of oligoarticular JIA include:

Uveitis, or inflammation inside the eye, which can lead to cataracts, glaucoma, or blindness if untreated, notes CreakyJoints.orgGradual changes to the jaw (temporomandibular), resulting in changes in the jaw’s shape and size, as well as the ability to open the mouthOne leg being shorter than the other, if the knee joint is affectedBeing shorter than other kids the same age who don’t have JIA

Oligoarticular JIA is more common in girls than boys and can be diagnosed around age 2 or 3. According to UpToDate.com, it is less commonly diagnosed after age 5 and almost never after age 10. Per UpToDate.com, “The typical child with oligoarticular JIA is a toddler girl who is noticed to be limping without complaint. Often, the caregiver notices that the child ‘walks funny’ in the morning, but after a little while seems fine. In many cases, the child has never complained of pain; the caregiver seeks medical advice only because the knee is swollen.”

Signs and Symptoms of Polyarticular JIA

Polyarticular JIA is a type of arthritis that affects five or more joints during the first six months after diagnosis, per KidsHealth.org. It may start out as fewer than five affected joints, then increase, or it may first appear with five or more joints that are swollen or painful. They are typically on both sides of the body, including the knees and wrists. Polyarticular JIA can affect both large and small joints, according to the Arthritis Foundation. Other symptoms can include:

A low red blood cell count, called anemiaA liver, spleen, or lymph nodes that are bigger than normalJoint damageInflammation in the lining of the heart or lungs

Signs and Symptoms of Systemic JIA

Systemic juvenile idiopathic arthritis (SJIA) isn’t common: It affects about 10 to 15 percent of all people with JIA. It happens when the body’s immune system goes into overdrive and attacks joints and causes rashes and fevers, according to the Hospital for Special Surgery in New York City. Systemic JIA can occur all at once or over a period of days or weeks. Symptoms of SJIA include:

Arthritis in the joints, causing swelling, heat, and painRashes, typically along with feverSwollen lymph nodes or an enlarged liver or spleenInflammation in the lining of the heart (pericarditis) or lungs (pleuritis)Fevers that occur daily, but don’t last a while

The Hospital for Special Surgery notes that “fevers typically occur around the same time every day. This can make the disease hard to diagnose, as children may look very ill when they have the fever but then totally normal when the fever goes away.”

This condition can also be known as juvenile spondylarthropathy, and it affects the joints of the lower body (such as the knees, hips, and ankles) as well as the spine and lower back. It causes arthritis where the ligaments, tendons, and joints attach to bone. It can develop after age 1 or any time before age 16, according to OrthoInfo. Symptoms of juvenile ERA include:

Joint pain in the knees, hips, ankles, and lower backJoint damageEye inflammationInflammatory bowel disease

Signs and Symptoms of Psoriatic Arthritis

Psoriatic arthritis in children is a form of juvenile idiopathic arthritis that comes with joint inflammation along with skin and nail issues. According to the Children’s Hospital of Philadelphia, psoriatic arthritis occurs in about a third of kids with psoriasis, describing it as “a chronic skin and nail disease characterized by red, scaly rashes and thick pitted fingernails.” Psoriatic arthritis cases make up about 6 percent of all cases of JIA. Symptoms, which can include some or many of the following, can be mild to severe:

Large and small joint swellingInflammation where the tendons and ligaments attach to boneSwelling of an entire finger or toeArthritis of the lower back or spineArthritis of the spineEye inflammationMorning stiffnessBack pain or stiffnessPitting or peeling of the nailsRed nail beds or cuticles

Signs and Symptoms of Undifferentiated JIA

Undifferentiated juvenile idiopathic arthritis is diagnosed when a person’s symptoms don’t fall easily into one of the above categories. Depending on the type of JIA, Kimura says that other symptoms of undifferentiated juvenile idiopathic arthritis can include:

Eye inflammationDifficulty straightening the affected leg, arm, or involved jointLimpingA change in gaitGradual changes to the jaw (temporomandibular) joint, resulting in changes in the jaw’s shape and size and the ability to open the mouthHigh fevers and rash

How Common Is Juvenile Idiopathic Arthritis?

As many as 1 to 4 in 1,000 children under age 16 may be affected, according the American College of Rheumatology. But since JIA is not always recognized, it’s unknown how common it is, according to Kimura. Even some physicians don’t realize that kids can have arthritis. While anyone of any age can be affected, the typical age of diagnosis ranges based on the type of JIA. “For example, oligoarticular JIA most often presents between the ages of 1 and 3, while enthesitis-related JIA patients are usually preteens and older when they first become symptomatic,” she says.

How JIA Is Diagnosed

Identifying JIA takes a combination of careful history taking, physical and musculoskeletal examination, and blood and imaging tests, usually by a pediatric rheumatologist who is trained in making the diagnosis and prescribing the right treatment, depending on the type of JIA, says Kimura. (The American College of Rheumatology offers a Find a Rheumatologist tool on its website, Rheumatology.org.) “Blood tests cannot make a diagnosis of JIA, because there are no specific tests that are diagnostic,” she says. Instead, such tests help rule out other conditions that may appear similar. In fact, she explains, “very often, blood tests are normal in children with JIA.” If a child under age 16 has symptoms that don’t go away after six weeks, a doctor may suspect JIA, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases. To diagnose JIA, a doctor will take a complete medical history, as JIA is an autoimmune disease and there can be a family history. They will ask about what kind of symptoms are occurring and how long they have been happening. The doctor will examine the patient’s joints and skin, watch the person walk, move their neck, open and close their hands, and determine if there is any sign of joint pain or joint damage that could affect bodily movement. They will also check the eyes for potential inflammation and look at the stomach and lymph nodes to see if they are swollen or painful. Several blood tests can evaluate if a person has:

Systemic inflammationAntibodies indicating there is an infection in the bodyLow levels of red blood cellsSigns that the kidneys and liver are working properly

Any of these results may indicate the presence of inflammation, but they aren’t all directly linked to JIA. Some people with JIA have normal test results, while others with abnormal results may have a different infection or illness, says Kimura. X-rays, ultrasounds, and MRIs may also be used to observe the joints for damage and inflammation, or can help identify other sources of pain such as a fracture, infection, or tumor. Research on JIA is still needed, says Kimura. Patients interested in learning more about research opportunities can find a registry and research network of pediatric rheumatology centers across North America. Newer medications to treat JIA “have worked wonders,” says Kimura, to rapidly relieve pain and other symptoms in JIA, drastically improving outcomes in the past 10 to 20 years. “Since newer treatments work so well, it is so important that children and adolescents who may have arthritis are seen as soon as possible by a trained pediatric rheumatologist,” she says.