Juvenile idiopathic arthritis is a group of related childhood diseases that begin by age 16 and cause persistent or recurring inflammation of the joints.
Certain forms of juvenile idiopathic arthritis may cause fever, rash, and lymph node swelling and may affect the heart.
Diagnosis is based on the child's symptoms and a physical examination because there is no single definitive laboratory test to diagnose the disease.
Children receive medications to reduce inflammation and treat pain.
Physical therapy, including flexibility exercises, helps enhance joint movement.
Juvenile idiopathic arthritis (JIA) is a group of uncommon diseases characterized by inflammation of joints (arthritis). JIA may also affect other organs or connective tissue.
Most children who have JIA have a disease that is not similar to adult rheumatoid arthritis, but a few children who have JIA do have a disease that is similar to adult rheumatoid arthritis.
The cause of JIA is unknown. Although JIA is not considered a hereditary disorder, hereditary factors may increase a child's chance of developing it. JIA is not due to an infection as some other kinds of arthritis are.
Classification of JIA
There are several forms of JIA. Although each form has different characteristics, they share similar features. The form is determined by results of a doctor's examination and laboratory tests. Forms include the following:
Oligoarticular JIA
Polyarticular JIA (rheumatoid factor negative or positive)
Enthesitis-related arthritis
Psoriatic JIA
Undifferentiated JIA
Systemic JIA
Children may have one form when they are first diagnosed but sometimes develop a different form during the course of their illness.
Oligoarticular JIA is the most common form and usually affects young girls. In this form, 4 or fewer ("oligo" means "few") joints are affected during the first 6 months of the disease. The knee is the most frequently affected joint.
Polyarticular JIA is the second most common form and begins in late childhood. In this form, 5 or more ("poly" means "many") joints are affected. This form is divided into 2 types: rheumatoid factor negative and rheumatoid factor positive. Rheumatoid factor is an antibody in the blood. High levels of rheumatoid factor can occur in people who have rheumatoid arthritis but can also occur in people who have other autoimmune disorders (for example, systemic lupus erythematosus, polymyositis, or systemic sclerosis).
Children who are rheumatoid factor positive have the rheumatoid factor antibody in their blood. The rheumatoid factor-positive type of JIA typically occurs in adolescent girls and is the same as adult rheumatoid arthritis. In both types, arthritis can affect the same joint on both sides of the body (for example, both knees or both hands) and frequently affects the small joints of the hands and feet.
Enthesitis-related arthritis involves arthritis and enthesitis (inflammation in areas where tendons and ligaments attach to bone). The arthritis often affects joints on only one side of the lower part of the body (such as the hip, knee, ankle, and foot). It is more common among older boys, and they may also develop arthritis in their lower spine.
Psoriatic JIA typically occurs in young girls but also occurs in older males and females (who are equally affected). Affected people may have the skin disease psoriasis or a family history of psoriasis in a parent or sibling.
Undifferentiated JIA is used to categorize children who have JIA but do not meet criteria for any one form or meet criteria for more than one.
Systemic JIA (Still disease) involves arthritis along with symptoms outside of the joints, including fever, rash, lymph node swelling, and inflammation around the heart and lungs.
Symptoms of JIA
JIA causes symptoms in the joints and sometimes the eyes, skin, or both. Complications can develop with any form of JIA.
Joint symptoms
Joint symptoms occur with any form of JIA.
The joints may be stiff when children awaken. Joints often become swollen and warm. Later, joints may become painful, but the pain may be milder than expected given the amount of swelling. Pain may become worse when the joint is moved. Children may be reluctant to walk or may limp. However, some children do not have any pain.
Joint pain lasts for years if untreated.
Enthesitis symptoms
Enthesitis can cause tenderness of the pelvis, hip bone, spine, kneecap, the shin just below the knee, the Achilles tendon, and the sole of the foot.
Eye symptoms
Eye inflammation can occur with any form of JIA but is most common in oligoarticular JIA and very rare in rheumatoid factor-positive polyarticular JIA and systemic JIA.
Inflammation typically affects the iris of the eye (iridocyclitis). Iridocyclitis in JIA usually does not cause symptoms (there is no pain or redness) but sometimes causes blurring of vision and irregular pupils. However, untreated iridocyclitis can lead to scarring, cataracts, glaucoma, and permanent loss of vision.
Rarely, children with enthesitis-related arthritis have eye redness, pain, and sensitivity to light.
Skin symptoms
Skin abnormalities occur mainly in psoriatic JIA and systemic JIA.
Children with psoriatic JIA may have rough, psoriasis-like patches on their skin; swollen fingers and toes; and pitted nails or nails that are partially or completely separated from the fingers (onycholysis).
Children with systemic JIA sometimes develop a short-lived rash made up of flat, pink-colored or salmon-colored patches with clear centers—mainly on the trunk and the upper part of the legs or arms. The rash appears for hours at a time (often in the evening with fever) and does not always appear in the same spot.
Systemic JIA symptoms
Systemic JIA causes fever and inflammation at sites other than the joints.
Children with systemic JIA typically develop a high fever and rash that frequently appear before joint pain and swelling. The fever occurs every day and is usually highest in the afternoon or evening (often 102.2° F [39° C] or higher). The fever may come and go for weeks. A child with fever may feel tired and irritable.
Inflammation may cause the liver, spleen, and lymph nodes to enlarge. Sometimes, inflammation develops in the membranes surrounding the heart (pericarditis) or in the membranes that cover the lungs (pleuritis) or develops inside the lungs, causing chest pain. This inflammation may cause fluid to accumulate around the heart, lungs, or other organs.
Complications of JIA
Any form of JIA can interfere with physical growth.
When JIA interferes with growth of the jaw, a small chin (micrognathia) can result.
Joints may become deformed if JIA is not treated. Even with treatment, long-standing (chronic) joint inflammation can eventually cause deformities of or permanent damage to the affected joints.
Diagnosis of JIA
A doctor's evaluation
Blood tests
A doctor diagnoses JIA based on the child's symptoms and the results of a physical examination.
There is no single, definitive laboratory test for JIA, but some blood tests help doctors distinguish one form of JIA from another. Blood is tested for a full blood count, rheumatoid factor, antinuclear antibodies, anti-cyclic citrullinated peptide antibodies, and a certain antigen called HLA-B27, some of which are present in some people with rheumatoid arthritis and related autoimmune diseases. Most children with systemic JIA do not have rheumatoid factor or antinuclear antibodies in their blood.
Other blood tests, such as ferritin, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR), might also be done. Increased levels of CRP and ESR indicate inflammation.
Children with JIA who do have antinuclear antibodies in their blood are at a higher risk of developing iridocyclitis. Children must be examined several times a year by an eye specialist (an ophthalmologist) for iridocyclitis regardless of whether symptoms are present because iridocyclitis may not cause any symptoms even though it is already causing eye inflammation. Children who have oligoarticular JIA or polyarticular JIA and who have antinuclear antibodies in their blood should have an eye examination every 3 months. Children who have oligoarticular or polyarticular JIA but who do not have antinuclear antibodies in their blood should have an eye examination every 6 months. Children who have systemic JIA should have an eye examination once or twice a year.
X-rays may be taken to look for characteristic changes in the bones or joints.
Treatment of JIA
Disease-modifying antirheumatic drugs (DMARDs)
Sometimes corticosteroids
Sometimes nonsteroidal anti-inflammatory drugs (NSAIDs) for symptom relief
As in adults, the different forms of JIA are treated with certain medications for arthritis called DMARDs.
DMARDs can slow the progression of JIA and have dramatically improved the lives of people who take them. Examples of these medications include
Methotrexate (which fights inflammation)
Etanercept, adalimumab, and infliximab (which block tumor necrosis factor, a protein involved in inflammation)
Anakinra and canakinumab (which block interleukin-1, a protein involved in inflammation)
Tocilizumab (which blocks interleukin-6)
Tofacitinib and upadacitinib (which block Janus kinase, an enzyme involved in inflammation)
Abatacept (which blocks cells that cause inflammation)
Doctors may inject corticosteroids directly into the affected joint or joints. Doctors try to avoid using systemic corticosteroids (such as prednisone given by mouth), but these medications may be required for children with severe systemic or polyarticular JIA. When systemic corticosteroids are necessary, the lowest possible dose is used to decrease the chance of long-term complications such as slowed growth,osteoporosis (brittle bones), cataracts, and osteonecrosis (death of bone tissue).
Iridocyclitis is initially treated with corticosteroid eye drops, which suppress inflammation, and with eye drops that widen (dilate) the pupil, which help prevent permanent eye damage. If this treatment is not enough, methotrexatemay be given and, if needed, etanercept, adalimumab, or infliximab. Eye surgery is needed occassionally if the eye has been damaged.
Typically, NSAIDs(such as naproxen and ibuprofen) are given to reduce symptoms and are most useful for enthesitis-related arthritis. However, although NSAIDs help relieve symptoms, they do not stop the progression of joint disease.
Other nonpharmacologic therapies that may be recommended include physical therapy or occupational therapy. For example, physical therapy may help improve flexibility and joint function as well as maintain strength.
Prognosis for JIA
Approximately 50% of children have symptom-free periods (remissions) within 5 years of treatment.
With early treatment, most children are able to lead active, normal lives.
Children who have rheumatoid factor-positive polyarticular JIA have a less favorable prognosis.
More Information
The following is an English-language resource that may be useful. Please note that The Manual is not responsible for the content of this resource.
The Arthritis Foundation: Juvenile Arthritis: Comprehensive information on various types of arthritis in children, including JIA, and information regarding living with a juvenile arthritis and transitioning from pediatric care to adult care
