Juvenile idiopathic arthritis (JIA)

Overview

Juvenile idiopathic arthritis (JIA), formerly called juvenile rheumatoid arthritis (JRA), is the most common chronic rheumatic disease of childhood. It is an umbrella diagnosis for a group of inflammatory arthritis disorders that begin before age 16, persist for at least six weeks, and have no identifiable cause.

JIA includes several distinct subtypes that differ in symptoms, disease course, affected joints, and risk of complications. While many forms primarily affect the joints, some can also involve the eyes or other organs. The exact cause remains unknown but is believed to involve a combination of genetic susceptibility and immune dysregulation.

JIA can arise in 6 different subtypes:

Oligoarthritis

The most common subtype which affects four or fewer joints, typically the large ones (knees, ankles, elbows).

Polyarthritis

Affects five or more joints, often on both sides of the body (both knees, both wrists, etc.). May affect large and small joints.

Psoriatic arthritis

Joint symptoms and a scaly rash behind the ears and/or on the eyelids, elbows, knees, belly button and scalp. Skin symptoms may occur before or after joint symptoms appear. May affect one or more joints, often the wrists, knees, ankles, fingers or toes.

Psoriatic Arthritis

Enthesitis-related/Spondyloarthritis

Affects where the muscles, ligaments or tendons attach to the bone (entheses). Commonly affects the hips, knees and feet, but may also affect the fingers, elbows, pelvis, chest, digestive tract (Crohn’s disease or ulcerative colitis) and lower back (ankylosing spondylitis). More common in boys; typically appears in children between the ages of eight and 15.

Undifferentiated

Symptoms don’t match up perfectly with any of the subtypes, but inflammation is present in one or more joints.

Systemic

Affects the entire body (joints, skin and internal organs). Symptoms may include a high spiking fever (103°F or higher) that lasts at least two weeks and rash.

Common Symptoms

Joint pain

Joint swelling

Joint stiffness

Reduced range of motion

Limping

Fatigue

Fever (particularly in systemic JIA)

Salmon-colored rash (systemic JIA)

Eye inflammation (uveitis)

Coexisting Diseases and Conditions

Chronic anterior uveitis

Cataracts

Glaucoma

Growth abnormalities

Osteoporosis

Psoriasis

Inflammatory bowel disease

Autoimmune thyroid disease

Type 1 diabetes (less commonly)

Risk Factors and Prevalence

Girls tend to be more than twice as likely as boys to develop JIA, though certain subtypes appear to affect boys more frequently. Further studies have shown that children aged 2-4 and 6-12 are at the highest risk of developing JIA. Studies have found that exposure to cigarette smoke puts children at further risk of developing JIA.

Recent Research

Sources

Sources
1. Ellis, J. A., Munro, J. E., & Ponsonby, A.-L. (2010). Possible environmental determinants of juvenile idiopathic arthritis. Rheumatology, 49(3), 411–425. https://doi.org/10.1093/rheumatology/kep383.
2. França, C. M. P., Sallum, A. M. E., Braga, A. L. F., Strufaldi, F. L., Silva, C. A. A., & Farhat, S. C. L. (2018). Risk Factors Associated with Juvenile Idiopathic Arthritis: Exposure to Cigarette Smoke and Air Pollution from Pregnancy to Disease Diagnosis. The Journal of Rheumatology, 45(2), 248–256. https://doi.org/10.3899/jrheum.161500.
3. Simon, T. A., Harikrishnan, G. P., Kawabata, H., Singhal, S., Brunner, H. I., & Lovell, D. J. (2020). Prevalence of co-existing autoimmune disease in juvenile idiopathic arthritis: A cross-sectional study. Pediatric Rheumatology, 18(1), 43. https://doi.org/10.1186/s12969-020-00426-9.
4. Rose, N. R., & Mackay, I. R. (2020). The Autoimmune Diseases (6th ed., pp. 676-687). Academic Press.
5. A Aeschlimann, F., & Quartier, P. (2019). Arthrites juvéniles idiopathiques [Juvenile idiopathic arthritis]. La Revue du praticien, 69(2), 188–194.
6. Zaripova, L. N., Midgley, A., Christmas, S. E., Beresford, M. W., Baildam, E. M., & Oldershaw, R. A. (2021). Juvenile idiopathic arthritis: from aetiopathogenesis to therapeutic approaches. Pediatric rheumatology online journal, 19(1), 135. https://doi.org/10.1186/s12969-021-00629-8
7. Prakken, B., Albani, S., & Martini, A. (2011). Juvenile idiopathic arthritis. Lancet (London, England), 377(9783), 2138–2149. https://doi.org/10.1016/S0140-6736(11)60244-4
8. Sudhakar, M., & Kumar, S. (2024). Juvenile Idiopathic Arthritis. Indian journal of pediatrics, 91(9), 949–958. https://doi.org/10.1007/s12098-023-04939-5