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# Juvenile idiopathic arthritis

Long-lasting joint inflammation in children under 16 with no other cause. It can also inflame the eye silently, so regular eye checks are vital.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Joint capsule](https://durgical.com/en/anatomy/articular-capsule-of-knee-joint/)
- [Wrist capsule](https://durgical.com/en/anatomy/wrist-joint-capsule/)
- [Hip capsule](https://durgical.com/en/anatomy/articular-capsule-of-hip-joint/)
- [Elbow capsule](https://durgical.com/en/anatomy/elbow-joint-capsule/)
- [Iris](https://durgical.com/en/anatomy/iris/)
- [Anterior chamber](https://durgical.com/en/anatomy/anterior-chamber-of-eyeball/)
- [Lens](https://durgical.com/en/anatomy/lens/)
- [Mandible](https://durgical.com/en/anatomy/mandible/)

## Why it happens

- [Chronic inflammation: causes, cells and features](https://durgical.com/en/general-pathology/chronic-inflammation-causes-cells-and-features/)
- [Synovial joints: capsule, synovial membrane and articular cartilage](https://durgical.com/en/histology/synovial-joints-capsule-synovial-membrane-and-articular-cartilage/)
- [Cartilage: hyaline, elastic, fibrocartilage](https://durgical.com/en/histology/cartilage-hyaline-elastic-fibrocartilage/)
- [Ossification, growth plate and bone remodeling](https://durgical.com/en/histology/ossification-growth-plate-and-bone-remodeling/)

## What it is

An umbrella term for chronic arthritis of unknown cause that begins before age 16 and lasts at least 6 weeks, after other causes have been excluded. It includes several subtypes with different patterns, from a few large joints to many small joints or a systemic form with fever and rash.

## Who gets it

The most common chronic rheumatic disease of childhood. Oligoarticular disease predominates in young girls; polyarticular rheumatoid factor–positive disease resembles adult rheumatoid arthritis in adolescent girls; enthesitis-related arthritis is more common in older boys. Access to paediatric rheumatology and eye screening is uneven across Colombia and Latin America, which delays diagnosis.

## Causes

- Autoimmune and autoinflammatory mechanisms; cause unknown
- Genetic susceptibility (HLA associations, such as HLA-B27 in enthesitis-related arthritis)
- Possible environmental triggers such as infections

## Risk factors

- Female sex (oligoarticular and polyarticular types)
- Early childhood onset (oligoarticular)
- Positive ANA: higher risk of uveitis
- HLA-B27 and family history of spondyloarthritis (enthesitis-related)
- Personal or family history of psoriasis (psoriatic JIA)

## Pathophysiology

Immune activation causes synovial inflammation with thickening (pannus), effusion and, if uncontrolled, erosion of cartilage and bone. Inflammation near growth plates can speed or slow growth, causing leg-length difference or a small jaw. In systemic JIA innate immune cytokines (IL-1, IL-6) drive fever, rash and serositis. Chronic anterior uveitis develops silently, especially in young ANA-positive girls.

## Classification

- Oligoarticular (1–4 joints in the first 6 months; persistent or extended)
- Polyarticular rheumatoid factor–negative (5 or more joints)
- Polyarticular rheumatoid factor–positive
- Systemic JIA (quotidian fever, evanescent salmon rash, arthritis)
- Enthesitis-related arthritis
- Psoriatic arthritis and undifferentiated arthritis (ILAR classification)

## Symptoms and signs

- Joint swelling, warmth and reduced movement, often of the knee, ankle or wrist
- Morning stiffness, limp or reluctance to walk after rest, rather than severe pain
- Fever spiking once or twice a day with a salmon-pink rash that comes and goes (systemic form)
- Enlarged lymph nodes, liver or [spleen](https://durgical.com/en/anatomy/spleen/), or [chest](https://durgical.com/en/anatomy/region/chest/) pain from serositis (systemic form)
- Heel pain or low back pain from enthesitis (enthesitis-related)
- Usually no eye symptoms despite uveitis; sometimes red eye or blurred vision

## Red flags

- Persistent fever, falling blood counts, falling ESR with very high ferritin, or confusion in systemic JIA (macrophage activation syndrome)
- A single hot, very painful joint with fever (septic arthritis)
- Night pain, bone pain, pallor, bruising or abnormal blood counts (leukaemia or bone tumour)
- Reduced vision or a red, painful eye
- Fever and infection signs during immunosuppressive or biologic treatment

## Diagnosis

**Clinical**
Diagnosis of exclusion: arthritis lasting at least 6 weeks with onset before 16 years and no other cause. The pattern and number of joints in the first 6 months define the subtype.

**Tests**
No single test confirms it. CBC, ESR/CRP, ANA (uveitis risk), rheumatoid factor and anti-CCP (prognosis), HLA-B27 when relevant; ferritin and clotting tests in systemic JIA. Joint fluid analysis when infection is suspected. Regular slit-lamp eye examinations screen for uveitis.

**Imaging**
Ultrasound and MRI show synovitis and effusion; plain radiographs exclude fractures and tumours and follow joint damage.

## Differential diagnosis

- Septic arthritis and osteomyelitis
- Reactive arthritis and post-viral arthritis; Lyme disease where it occurs
- Acute leukaemia and bone tumours
- Systemic lupus erythematosus and other connective tissue diseases
- Kawasaki disease and other causes of prolonged fever in children (for systemic JIA)
- Trauma and orthopaedic conditions

## Goal of treatment

Achieve inactive disease, protect joints and growth, prevent eye damage from uveitis, and allow normal school, play and development.

## Treatment

**Medical**
NSAIDs for symptoms and intra-articular glucocorticoid injections for affected joints, especially in oligoarticular disease.

**Medical**
Methotrexate as the main conventional disease-modifying drug for persistent or polyarticular disease.

**Medical**
Biologics for disease not controlled or severe forms: TNF inhibitors, or IL-1 and IL-6 blockers for systemic JIA; systemic glucocorticoids short-term for severe systemic features.

**Rehabilitation**
Physiotherapy and occupational therapy to keep range of motion, strength and function; splints when needed; school and psychosocial support.

**Follow-up**
Ophthalmological screening with slit-lamp examination at intervals set by subtype and ANA status; monitoring of growth, blood counts, [liver](https://durgical.com/en/anatomy/liver/) tests and infection risk on treatment; vaccinations updated before immunosuppression.

## Drugs for this condition

- [Adalimumab](https://durgical.com/en/pharmacology/adalimumab/)
- [Etanercept](https://durgical.com/en/pharmacology/etanercept/)
- [Golimumab](https://durgical.com/en/pharmacology/golimumab/)
- [Tocilizumab](https://durgical.com/en/pharmacology/tocilizumab/)
- [Secukinumab](https://durgical.com/en/pharmacology/secukinumab/)
- [Tofacitinib](https://durgical.com/en/pharmacology/tofacitinib/)
- [Abatacept](https://durgical.com/en/pharmacology/abatacept/)

## Complications

- Chronic anterior uveitis leading to cataract, glaucoma, band keratopathy and vision loss
- Joint damage, contractures and disability
- Growth disturbance: leg-length difference, small jaw (micrognathia), short stature
- Macrophage activation syndrome in systemic JIA
- Osteoporosis and infections related to treatment

## Prognosis

Modern treatment allows most children to reach inactive disease, though many still have active arthritis into adulthood. Oligoarticular persistent disease has the best outlook; rheumatoid factor–positive polyarticular and systemic forms carry more risk of damage.

## Test yourself

Think of the answer, then tap the question to see it.

## What defines juvenile idiopathic arthritis?

Arthritis of unknown cause beginning before age 16 and lasting at least 6 weeks, after excluding other causes.

## Which JIA patients have the highest risk of uveitis?

Young girls with oligoarticular disease and positive ANA.

## Why do children with JIA need regular slit-lamp eye examinations?

Because chronic anterior uveitis is often painless and silent but can cause blindness if not detected.

## What are the classic features of systemic JIA?

Daily spiking fever, an evanescent salmon-pink rash, arthritis, lymphadenopathy, organomegaly and serositis.

## Which life-threatening complication can occur in systemic JIA?

Macrophage activation syndrome.

[Add to my cards (5)](https://durgical.app/estudiar/?add=/en/conditions/juvenile-idiopathic-arthritis/)

## Related conditions

- [Uveitis](https://durgical.com/en/conditions/uveitis/)
- [Cataract](https://durgical.com/en/conditions/cataract/)
- [Septic Arthritis of the Knee](https://durgical.com/en/conditions/septic-arthritis-of-the-knee/)
- [Reactive arthritis](https://durgical.com/en/conditions/reactive-arthritis/)
- [Lyme disease](https://durgical.com/en/conditions/lyme-disease/)
- [Acute leukaemia (AML and ALL)](https://durgical.com/en/conditions/acute-leukaemia/)
- [Systemic lupus erythematosus](https://durgical.com/en/conditions/systemic-lupus-erythematosus/)
- [Kawasaki disease](https://durgical.com/en/conditions/kawasaki-disease/)
- [Rheumatoid arthritis](https://durgical.com/en/conditions/rheumatoid-arthritis/)
- [Psoriatic arthritis](https://durgical.com/en/conditions/psoriatic-arthritis/)
- [Ankylosing spondylitis](https://durgical.com/en/conditions/ankylosing-spondylitis/)
- [Osteoporosis](https://durgical.com/en/conditions/osteoporosis/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Juvenile idiopathic arthritis](https://medlineplus.gov/ency/article/000451.htm) (MedlinePlus (U.S. National Library of Medicine), 2025).

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/juvenile-idiopathic-arthritis/