skip to main content
ukmla 2026

Juvenile Idiopathic Arthritis

Chronic inflammatory arthritis in children (<16 years) persisting for >6 weeks with no other identifiable cause — subtypes include oligoarticular (most common), polyarticular, and systemic-onset (Still disease)

Review date
reviewed 2026-04-05
Reading time
6 min read
Author
Dr Kola Tytler MBBS CertHE MBA MSt MRCGP
Paediatricsless-commonchronic
On this page
Condition details
Paediatrics
less-common
6 min read
reviewed 2026-04-05
practice ukmla questions →

About This Page

This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.

Key points

  • JIA = arthritis in a child <16 years, lasting >6 weeks, with no other identifiable cause
  • Subtypes: oligoarticular (1–4 joints, most common, peak 2–4 years, girls), polyarticular (5+ joints), systemic-onset (Still disease — quotidian fever, salmon-pink rash, serositis, hepatosplenomegaly)
  • Oligoarticular JIA: high risk of chronic anterior uveitis — ASYMPTOMATIC, ANA-positive children need regular slit-lamp screening every 3–4 months
  • First-line: NSAIDs + intra-articular steroid injections. If inadequate: methotrexate
  • Biologic agents (anti-TNF: etanercept, adalimumab; anti-IL-6: tocilizumab; anti-IL-1: anakinra/canakinumab) for refractory disease
  • Always exclude septic arthritis if single hot swollen joint — joint aspiration if diagnostic uncertainty

Overview

JIA is the most common chronic inflammatory arthritis in childhood. It encompasses a heterogeneous group of conditions characterised by persistent joint inflammation. The major subtypes are oligoarticular (1–4 joints, most common), polyarticular (5+ joints, RF-positive or RF-negative), systemic-onset (Still disease — with systemic features), enthesitis-related arthritis (associated with HLA-B27), and psoriatic arthritis. Chronic anterior uveitis is a particularly important extra-articular complication, as it is asymptomatic and can lead to blindness if not detected by routine slit-lamp screening.

Epidemiology

JIA prevalence is approximately 1 per 1,000 children in the UK. Oligoarticular JIA is the most common subtype (~50%) and peaks at 2–4 years with a female predominance. Systemic-onset JIA has equal sex distribution and can present at any age. Enthesitis-related arthritis is more common in boys aged >6 years and is associated with HLA-B27.

Clinical Features

Symptoms
Joint swelling, stiffness, and pain — morning stiffness >30 min (improves with activity)
Limp or reluctance to walk in young children (may not complain of pain)
Systemic-onset: daily spiking (quotidian) fever — typically spikes once or twice daily and returns to normal between spikes
Salmon-pink evanescent macular rash (systemic-onset — appears with fever, fades when afebrile)
Visual symptoms are usually ABSENT in uveitis — screening is essential
Signs
Joint swelling, warmth, limited range of motion
Gelling phenomenon: stiffness after periods of rest
Limb length discrepancy (overgrowth of affected limb from chronic inflammation stimulating growth plate)
Hepatosplenomegaly and lymphadenopathy (systemic-onset)
Pericardial rub or effusion (systemic-onset — serositis)

Investigations

First-line
Inflammatory markersESR and CRP — elevated in active disease. May be markedly raised in systemic-onset
FBCAnaemia of chronic disease, thrombocytosis, leucocytosis. In systemic-onset: ferritin may be very high (consider MAS if ferritin falling rapidly)
ANAPositive in ~60–70% of oligoarticular JIA — identifies children at higher risk of chronic anterior uveitis
Second-line
Rheumatoid factor and anti-CCPRF-positive polyarticular JIA has poorer prognosis. RF is negative in oligoarticular and systemic-onset
HLA-B27Associated with enthesitis-related arthritis
Joint aspirationIf septic arthritis cannot be excluded — essential if single hot swollen joint with fever
Specialist
Slit-lamp examinationESSENTIAL screening for chronic anterior uveitis — every 3–4 months in ANA-positive oligoarticular JIA
MRITo assess synovitis, effusion, cartilage and bone damage — especially useful in early disease

Management

NICE NG1 and BSR/BSPAR guidelines
1
First-line
  • NSAIDs: ibuprofen or naproxen for symptom relief
  • Intra-articular corticosteroid injections (triamcinolone hexacetonide) — effective in oligoarticular JIA
  • Physiotherapy and occupational therapy — essential to maintain joint function
2
DMARDs
  • Methotrexate: first-line DMARD if inadequate response to NSAIDs and intra-articular steroids, or polyarticular disease
  • Start within 3–6 months if active arthritis persists
  • Monitor: FBC, LFTs, renal function. Give folic acid supplementation
3
Biologic therapy
  • If inadequate response to methotrexate: anti-TNF (etanercept, adalimumab), anti-IL-6 (tocilizumab)
  • Systemic-onset JIA: anti-IL-1 (anakinra, canakinumab) or anti-IL-6 (tocilizumab) are first-line biologics
  • Uveitis refractory to topical steroids and methotrexate: adalimumab
4
Uveitis screening
  • All children with JIA need ophthalmology screening
  • Highest risk: ANA-positive, oligoarticular, young onset — screen every 3–4 months
  • Treatment: topical corticosteroid eye drops, mydriatics, methotrexate/adalimumab if refractory

Complications

  • Chronic anterior uveitis: Asymptomatic — can cause posterior synechiae, band keratopathy, cataract, glaucoma, blindness
  • Growth disturbance: Localised overgrowth (limb length discrepancy) or systemic growth suppression (corticosteroids)
  • Macrophage activation syndrome (MAS): Life-threatening complication of systemic-onset JIA — falling ferritin, pancytopenia, coagulopathy, hepatitis
  • Joint damage and disability: Erosions, joint destruction if inadequately treated
  • Amyloidosis: Rare long-term complication of chronic inflammation
UKMLA Exam Tips
  • 1Oligoarticular JIA is the most common subtype — young girl, 1–4 large joints, ANA-positive, risk of uveitis
  • 2Uveitis in JIA is ASYMPTOMATIC and CHRONIC — regular slit-lamp screening is essential to prevent blindness
  • 3Systemic-onset (Still disease): quotidian fever + salmon-pink rash + serositis + hepatosplenomegaly + very high ferritin
  • 4Single hot swollen joint in a child: must exclude septic arthritis before diagnosing JIA
  • 5Limb length discrepancy: chronic knee arthritis stimulates ipsilateral growth plate — affected leg becomes longer
  • 6MAS: falling ferritin (paradoxically — as macrophages consume it) + pancytopenia + DIC + liver failure

Put your reading into practice

Topic-specific question practice is not linked for this article yet.

Choose UKMLA questions from the existing bank. General exam practice covers your selected topics; it is not filtered to this article. Your usual question-bank access applies.

Choose UKMLA practice

After your session, return to this section to revisit the reading and choose your next review.

Verified Sources & References

NICE NG1 — Juvenile idiopathic arthritis
Your learning path

Save your place and choose what comes next

sign in to save your learning

Paediatrics · Article 20 of 32