The cause of JIA is not known. It is thought to be an autoimmune illness. This means the body attacks and destroys healthy body tissue by mistake.

JIA most often develops before age 16. Symptoms may start as early as 6 months old.

The International League of Associations for Rheumatology (ILAR) has proposed the following way of grouping this type of childhood arthritis:

• Systemic-onset JIA. Involves joint swelling or pain, fevers, and rash. It is the least common type but it can be the most severe. It appears to be different than the other types of JIA and is similar to Adult Onset Stills Disease.
• Polyarthritis. Involves many joints. This form of JIA may turn into rheumatoid arthritis. It may involve 5 or more large and small joints of the legs and arms, as well as the jaw and neck. Rheumatoid factor may be present.
• Oligoarthritis (persistent and extended). Involves 1 to 4 joints, most often the wrists, or knees. It also affects the eyes.
• Enthesitis-related arthritis. Resembles spondyloarthritis in adults and often involves the sacroiliac joint.
• Psoriatic arthritis. Diagnosed in children who have arthritis and psoriasis or nail disease, or have a close family member with psoriasis.

Symptoms of JIA may include:

• Swollen, red, or warm joint
• Limping or problems using a limb
• Sudden high fever, which may come back
• Rash (on trunk and extremities) that comes and goes with fever
• Stiffness, pain, and limited movement of a joint
• Low back pain that does not go away
• Bodywide symptoms such as pale skin, swollen lymph gland, and a sick appearance

JIA can also cause eye problems called uveitis, iridocyclitis, or iritis. There may be no eye symptoms. When eye symptoms occur, they can include:

• Red eyes
• Eye pain, which may get worse when looking at light (photophobia)
• Vision changes

The physical exam may show swollen, warm, and tender joints that hurt to move. The child may have a rash. Other signs include:

• Swollen liver
• Swollen spleen
• Swollen lymph nodes

Blood tests may include:

• Rheumatoid factor
• Anti-cyclic citrullinated peptide (CCP) antibody
• Erythrocyte sedimentation rate (ESR)
• Antinuclear antibody (ANA)
• Complete blood count (CBC)
• HLA-B27

Any or all of these blood tests may be normal in children with JIA.

The health care provider may place a small needle into a swollen joint to remove fluid. This can help to find the cause of the arthritis. It can also help relieve pain. The provider may inject steroids into the joint to help reduce swelling.

Other tests that may be done include:

• X-ray of a joint
• Bone scan
• X-ray of the chest
• ECG
• Regular eye exam by an ophthalmologist -- This should be done even if there are no eye symptoms.

Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen may be enough to control symptoms when only a small number of joints are involved.

Corticosteroids may be used for more severe flare-ups to help control symptoms. Because of their toxicity, long-term use of these medicines should be avoided in children.

Children who have arthritis in many joints, or who have fever, rash, and swollen glands may need other medicines. These are called disease-modifying antirheumatic drugs (DMARDs). They can help reduce swelling in the joints or body. DMARDs include:

• Methotrexate
• Biologic DMARDs such as anti-tumor necrosis factor (TNF) agents, IL-1 inhibitors and IL-6 inhibitors.

Children with JIA need to stay active.

Exercise will help keep their muscles and joints strong and mobile.

• Walking, bicycling, and swimming may be good activities.
• Children should learn to warm up before exercising.
• Talk to the doctor or physical therapist about exercises to do when your child is having pain.

Children who have sadness or anger about their arthritis may need extra support.

Some children with JIA may need surgery, including joint replacement.

Children with only a few affected joints may have no symptoms for a long period.

In many children, the disease will become inactive and cause very little joint damage.

The severity of the disease depends on the number of affected joints. It is less likely that symptoms will go away in these cases. These children more often have long-term (chronic) pain, disability, and problems at school. Some children may continue to have arthritis as adults.

Complications may include:

• Wearing away or destruction of joints (can occur in people with more severe JIA)
• Slow rate of growth
• Uneven growth of an arm or leg
• Loss of vision or decreased vision from chronic uveitis (this problem may be severe, even when the arthritis is not very severe)
• Anemia
• Swelling around the heart (pericarditis)
• Long-term (chronic) pain, poor school attendance
• Macrophage activation syndrome, a severe illness that may develop with systemic JIA

Contact your provider if:

• You, or your child, notice symptoms of JIA
• Symptoms get worse or do not improve with treatment
• New symptoms develop

There is no known prevention for JIA.

Juvenile rheumatoid arthritis (JRA)

Beukelman T, Nigrovic PA. Juvenile idiopathic arthritis: an idea whose time has gone? J Rheumatol. 2019;46(2):124-126. PMID: 30710000 pubmed.ncbi.nlm.nih.gov/30710000/.

Nordal EB, Rygg M, Fasth A. Clinical features of juvenile idiopathic arthritis. In: Hochberg MC, Gravallese EM,  Smolen JS, van der Heijde D, Weinblatt ME, Weisman MH, eds. Rheumatology. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 105.

Ombrello MJ, Arthur VL, Remmers EF, et al. Genetic architecture distinguishes systemic juvenile idiopathic arthritis from other forms of juvenile idiopathic arthritis: clinical and therapeutic implications. Ann Rheum Dis. 2017;76(5):906-913. PMID: 27927641 pubmed.ncbi.nlm.nih.gov/27927641/.

Onel KB, Horton DB, Lovell DJ, et al. 2021 American College of Rheumatology Guideline for the treatment of juvenile idiopathic arthritis: therapeutic approaches for oligoarthritis, temporomandibular joint arthritis, and systemic juvenile idiopathic arthritis. Arthritis Care Res (Hoboken). 2022;74(4):521-537. PMID: 35233986 pubmed.ncbi.nlm.nih.gov/35233986/.

Schulert GS, Minoia F, Bohnsack J, et al. Effect of biologic therapy on clinical and laboratory features of macrophage activation syndrome associated with systemic juvenile idiopathic arthritis. Arthritis Care Res (Hoboken). 2018;70(3):409-419. PMID: 28499329 pubmed.ncbi.nlm.nih.gov/28499329/.

Ter Haar NM, van Dijkhuizen EHP, Swart JF, et al. Treatment to target using recombinant interleukin-1 receptor antagonist as first-line monotherapy in new-onset systemic juvenile idiopathic arthritis: results from a five year follow-up study. Arthritis Rheumatol. 2019;71(7):1163-1173. PMID: 30848528 pubmed.ncbi.nlm.nih.gov/30848528/.

Wu EY, Rabinovich CE. Juvenile idiopathic arthritis. In: Kliegman RM, St. Geme JW, Schor NF, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 180.

Updated by: Neil J. Gonter, MD, Assistant Professor of Medicine, Columbia University, New York, NY, and private practice specializing in Rheumatology at Rheumatology Associates of North Jersey, Teaneck, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.