Juvenile idiopathic arthritis (JIA) is an umbrella term for the chronic arthritides of childhood beginning before 16 years of age and persisting for at least 6 weeks, after exclusion of infective, traumatic, malignant, and other defined causes. The International League of Associations for Rheumatology (ILAR) criteria stratify JIA into clinically distinct categories — oligoarticular, polyarticular rheumatoid-factor-negative, polyarticular rheumatoid-factor-positive, systemic, psoriatic, enthesitis-related, and undifferentiated — that differ in age of onset, joint pattern, extra-articular features, autoantibody status, and prognosis. The underlying mechanisms span a spectrum from predominantly autoimmune (oligo-/polyarticular, RF+ resembling adult rheumatoid arthritis) to predominantly autoinflammatory (systemic JIA, now recognised as part of the Still's disease continuum with adult-onset Still's disease). Long-term morbidity is driven by joint damage and deformity, chronic uveitis (notably in ANA-positive oligoarticular JIA), and — in systemic JIA — by macrophage activation syndrome. Management is risk-stratified and uses NSAIDs, intra-articular and systemic glucocorticoids, conventional DMARDs (methotrexate), and biologics targeting TNF, IL-1, or IL-6.
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name: Juvenile Idiopathic Arthritis
creation_date: '2026-05-12T00:00:00Z'
updated_date: '2026-05-12T21:00:00Z'
description: >-
Juvenile idiopathic arthritis (JIA) is an umbrella term for the chronic
arthritides of childhood beginning before 16 years of age and persisting for
at least 6 weeks, after exclusion of infective, traumatic, malignant, and
other defined causes. The International League of Associations for
Rheumatology (ILAR) criteria stratify JIA into clinically distinct
categories — oligoarticular, polyarticular rheumatoid-factor-negative,
polyarticular rheumatoid-factor-positive, systemic, psoriatic,
enthesitis-related, and undifferentiated — that differ in age of onset, joint
pattern, extra-articular features, autoantibody status, and prognosis. The
underlying mechanisms span a spectrum from predominantly autoimmune
(oligo-/polyarticular, RF+ resembling adult rheumatoid arthritis) to
predominantly autoinflammatory (systemic JIA, now recognised as part of the
Still's disease continuum with adult-onset Still's disease). Long-term
morbidity is driven by joint damage and deformity, chronic uveitis (notably
in ANA-positive oligoarticular JIA), and — in systemic JIA — by macrophage
activation syndrome. Management is risk-stratified and uses NSAIDs,
intra-articular and systemic glucocorticoids, conventional DMARDs
(methotrexate), and biologics targeting TNF, IL-1, or IL-6.
categories:
- Pediatric Rheumatologic Disease
- Autoimmune Disease
- Autoinflammatory Disease
- Chronic Arthritis
has_subtypes:
- name: Oligoarticular
display_name: Oligoarticular JIA
subtype_term:
preferred_term: oligoarticular juvenile idiopathic arthritis
term:
id: MONDO:0019433
label: oligoarticular juvenile idiopathic arthritis
description: >-
Up to four joints affected during the first six months. The most common
JIA category in young children, with strong association with chronic
anterior uveitis (particularly in ANA-positive girls). May extend to a
polyarticular course.
- name: Polyarticular RF-negative
display_name: Polyarticular JIA, RF-negative
subtype_term:
preferred_term: polyarticular juvenile idiopathic arthritis
term:
id: MONDO:0018456
label: polyarticular juvenile idiopathic arthritis
description: >-
Five or more joints affected in the first six months with negative
rheumatoid factor. Symmetric or asymmetric involvement; clinically
heterogeneous. Grounded to the broader polyarticular-JIA MONDO term;
MONDO does not yet split RF-negative as a distinct identifier.
- name: Polyarticular RF-positive
display_name: Polyarticular JIA, RF-positive
subtype_term:
preferred_term: polyarticular juvenile idiopathic arthritis
term:
id: MONDO:0018456
label: polyarticular juvenile idiopathic arthritis
description: >-
Five or more joints affected with persistent rheumatoid factor
positivity on two tests at least three months apart. Immunogenetically
most similar to adult rheumatoid arthritis; tends to be aggressive and
erosive. Grounded to the broader polyarticular-JIA MONDO term; MONDO
does not yet split RF-positive as a distinct identifier.
- name: Systemic
display_name: Systemic JIA (Still's disease)
description: >-
Arthritis preceded or accompanied by quotidian fever, evanescent
salmon-coloured rash, lymphadenopathy, hepatosplenomegaly, and
serositis. Recognised as part of the Still's disease continuum with
adult-onset Still's disease and complicated by macrophage activation
syndrome. (No dedicated MONDO subtype term identified by exact-label
lookup; left ungrounded until verified.)
- name: Psoriatic
display_name: Psoriatic JIA
description: >-
Arthritis with psoriasis, or arthritis plus at least two of: dactylitis,
nail pitting / onycholysis, or psoriasis in a first-degree relative.
(No dedicated MONDO subtype term identified by exact-label lookup;
left ungrounded until verified.)
- name: Enthesitis-related
display_name: Enthesitis-Related JIA
subtype_term:
preferred_term: enthesitis-related juvenile idiopathic arthritis
term:
id: MONDO:0019437
label: enthesitis-related juvenile idiopathic arthritis
description: >-
Arthritis and/or enthesitis with associated features (HLA-B27,
sacroiliitis, acute anterior uveitis, or family history of
spondyloarthropathy). Predominantly affects older boys; overlaps with
juvenile-onset spondyloarthritis.
- name: Undifferentiated
description: >-
JIA that does not fulfil criteria for any of the above categories or
fulfils criteria for more than one. A residual ILAR category.
pathophysiology:
- name: Synovial Leukocyte Infiltration
description: >-
T-cell and macrophage recruitment to the synovial membrane is the
initiating cellular event of synovitis in JIA, with the relative
contribution of adaptive autoimmunity versus innate autoinflammation
varying by ILAR subtype.
cell_types:
- preferred_term: T cell
term:
id: CL:0000084
label: T cell
- preferred_term: macrophage
term:
id: CL:0000235
label: macrophage
biological_processes:
- preferred_term: immune response
modifier: ABNORMAL
term:
id: GO:0006955
label: immune response
locations:
- preferred_term: synovial membrane
term:
id: UBERON:0002018
label: synovial membrane of synovial joint
downstream:
- target: Synovial Hyperplasia
causal_link_type: DIRECT
- target: Cytokine-Mediated Articular Damage
causal_link_type: DIRECT
- name: Synovial Hyperplasia
description: >-
Activated synovial fibroblasts and resident synoviocytes proliferate
under cytokine drive, producing the thickened, vascularised synovium
(pannus-like membrane in long-standing disease) that supports
ongoing inflammation and joint damage.
cell_types:
- preferred_term: synovial cell
term:
id: CL:0000214
label: synovial cell
locations:
- preferred_term: synovial membrane
term:
id: UBERON:0002018
label: synovial membrane of synovial joint
downstream:
- target: Cytokine-Mediated Articular Damage
causal_link_type: DIRECT
- name: Cytokine-Mediated Articular Damage
description: >-
Pro-inflammatory cytokine production (notably TNF, IL-1, IL-6) by
infiltrating leukocytes and hyperplastic synovium drives cartilage
and bone destruction at the joint, the proximate mechanism of the
long-term joint-damage phenotype across non-systemic JIA categories.
biological_processes:
- preferred_term: cytokine production
modifier: INCREASED
term:
id: GO:0001816
label: cytokine production
locations:
- preferred_term: synovial membrane
term:
id: UBERON:0002018
label: synovial membrane of synovial joint
downstream:
- target: Arthritis
causal_link_type: DIRECT
- name: Systemic Autoinflammation (sJIA)
description: >-
Systemic JIA is dominated by innate-immune activation with prominent
IL-1 and IL-6 signalling, distinguishing it pathophysiologically from
the more T-cell-driven oligo-/polyarticular categories. Under current
consensus it is considered the same entity as adult-onset Still's
disease.
evidence:
- reference: PMID:38756937
reference_title: "Diagnosing and Treating Systemic Juvenile Idiopathic Arthritis and Adult-Onset Still's Disease as Part of the Still's Disease Continuum."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "sJIA and AOSD are rare autoinflammatory disorders that have similar pathophysiological and clinical features."
explanation: Directly supports systemic JIA as an autoinflammatory disorder sharing pathophysiology with adult-onset Still's disease.
- reference: PMID:39317417
reference_title: "EULAR/PReS recommendations for the diagnosis and management of Still's disease, comprising systemic juvenile idiopathic arthritis and adult-onset Still's disease."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still's disease (AOSD) are considered the same disease, but a common approach for diagnosis and management is still missing."
explanation: Supports the consensus position that systemic JIA and adult-onset Still's disease are the same disease (the Still's disease continuum).
biological_processes:
- preferred_term: interleukin-1 mediated signaling pathway
modifier: INCREASED
term:
id: GO:0070498
label: interleukin-1-mediated signaling pathway
- preferred_term: interleukin-6 mediated signaling pathway
modifier: INCREASED
term:
id: GO:0070102
label: interleukin-6-mediated signaling pathway
downstream:
- target: Fever
causal_link_type: DIRECT
phenotypes:
- category: Musculoskeletal
name: Arthritis
frequency: VERY_FREQUENT
description: >-
Chronic arthritis of one or more joints lasting at least six weeks is
the defining feature across all ILAR JIA categories.
phenotype_term:
preferred_term: Arthritis
term:
id: HP:0001369
label: Arthritis
evidence:
- reference: PMID:29037901
reference_title: "HLA-DRB1 alleles and juvenile idiopathic arthritis: Diagnostic clues emerging from a meta-analysis."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Juvenile Idiopathic Arthritis (JIA) is characterized with a variable pattern of articular involvement and systemic symptoms"
explanation: Supports articular involvement (arthritis) as a defining clinical feature of JIA.
- category: Musculoskeletal
name: Joint Swelling
frequency: VERY_FREQUENT
description: >-
Swelling and warmth of affected joints from synovial inflammation and
effusion. Often the presenting sign in oligo-/polyarticular JIA.
phenotype_term:
preferred_term: Joint swelling
term:
id: HP:0001386
label: Joint swelling
- category: Musculoskeletal
name: Joint Stiffness
frequency: VERY_FREQUENT
description: >-
Morning and post-rest stiffness that improves with activity; a
characteristic feature of chronic inflammatory arthritis in children.
phenotype_term:
preferred_term: Joint stiffness
term:
id: HP:0001387
label: Joint stiffness
- category: Musculoskeletal
name: Arthralgia
frequency: VERY_FREQUENT
description: >-
Joint pain, often disproportionate to apparent swelling in younger
children where pain may present as reluctance to bear weight, limp, or
behavioural change rather than verbalised complaint.
phenotype_term:
preferred_term: Arthralgia
term:
id: HP:0002829
label: Arthralgia
- category: Musculoskeletal
name: Joint Deformity
frequency: FREQUENT
description: >-
Long-standing or inadequately treated disease leads to fixed joint
deformities, most commonly involving hands, wrists, and knees, with
higher risk in polyarticular and RF-seropositive subsets.
phenotype_term:
preferred_term: Joint deformity
term:
id: HP:0001376
label: Limitation of joint mobility
evidence:
- reference: PMID:29848426
reference_title: "Spectrum of Joint Deformities in Children with Juvenile Idiopathic Arthritis."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Most common joints involved were hand (50%), wrist (50%), and knee (35.7%)."
explanation: Cross-sectional ILAR-defined JIA cohort directly supports hand, wrist, and knee as the joints most commonly affected by deformity in JIA.
- category: Constitutional
name: Fever
subtype: Systemic
frequency: VERY_FREQUENT
description: >-
Quotidian or quotidian-like fever is a defining feature of systemic
JIA (Still's disease) and uncommon in the non-systemic categories;
qualified here to the Systemic subtype.
phenotype_term:
preferred_term: Fever
term:
id: HP:0001945
label: Fever
- category: Ophthalmologic
name: Chronic Anterior Uveitis
subtype: Oligoarticular
frequency: FREQUENT
description: >-
Chronic, often asymptomatic anterior uveitis is the major
extra-articular complication of oligoarticular JIA, particularly in
ANA-positive young girls, and a leading cause of visual morbidity
if not detected by routine slit-lamp screening. Acute symptomatic
anterior uveitis also occurs in enthesitis-related JIA. Subtype-
qualified here to oligoarticular JIA, the highest-risk category.
phenotype_term:
preferred_term: Anterior uveitis
term:
id: HP:0012122
label: Anterior uveitis
temporality: CHRONIC
genetic:
- name: HLA-DRB1
gene_term:
preferred_term: HLA-DRB1
term:
id: hgnc:4948
label: HLA-DRB1
association: Susceptibility
notes: >-
HLA class II is the dominant genetic susceptibility locus for JIA, with
`HLA-DRB1` alleles showing subtype-specific risk associations
(HLA-DRB1*08 in oligoarticular and polyarticular JIA; HLA-DRB1*11
additionally predisposing to oligoarticular JIA; HLA-DRB1*01 and
HLA-DRB1*04 in RF-positive polyarticular JIA; HLA-DRB1*04 in systemic
JIA).
evidence:
- reference: PMID:29037901
reference_title: "HLA-DRB1 alleles and juvenile idiopathic arthritis: Diagnostic clues emerging from a meta-analysis."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Genetic predisposition to JIA is mainly due to HLA class II molecules (HLA-DRB1, HLA-DPB1), although HLA class I molecules and non-HLA genes have been implicated, too."
explanation: Meta-analysis directly supports HLA-DRB1 as a primary genetic susceptibility locus for JIA.
- reference: PMID:29037901
reference_title: "HLA-DRB1 alleles and juvenile idiopathic arthritis: Diagnostic clues emerging from a meta-analysis."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "HLA-DRB1*08 is a strong factor predisposing to JIA, both for oligo-articular and poly-articular forms"
explanation: Meta-analysis directly supports HLA-DRB1*08 as a predisposing allele for both oligoarticular and polyarticular JIA.
- reference: PMID:29037901
reference_title: "HLA-DRB1 alleles and juvenile idiopathic arthritis: Diagnostic clues emerging from a meta-analysis."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "iii) HLA-DRB1*11"
explanation: Meta-analysis confirms HLA-DRB1*11 as an additional predisposing allele for oligoarticular JIA.
treatments:
- name: NSAIDs
description: >-
Non-steroidal anti-inflammatory drugs are first-line symptom control
for active arthritis and a useful diagnostic/therapeutic trial in
early disease.
treatment_term:
preferred_term: NSAID therapy
term:
id: MAXO:0000221
label: NSAID therapy
- name: Intra-articular and Systemic Glucocorticoids
description: >-
Intra-articular steroid injection (most often triamcinolone) is
standard for oligoarticular JIA. Short-course systemic
glucocorticoids are used as a bridge to DMARDs and as front-line
therapy in active systemic JIA.
treatment_term:
preferred_term: glucocorticoid therapy
term:
id: NCIT:C15986
label: Pharmacotherapy
therapeutic_agent:
- preferred_term: triamcinolone
term:
id: CHEBI:9667
label: triamcinolone
- name: Methotrexate (conventional DMARD)
description: >-
Methotrexate is the conventional synthetic DMARD of first choice for
polyarticular and extended-oligoarticular JIA, slowing radiographic
progression and inducing remission.
treatment_term:
preferred_term: methotrexate therapy
term:
id: NCIT:C15986
label: Pharmacotherapy
therapeutic_agent:
- preferred_term: methotrexate
term:
id: CHEBI:44185
label: methotrexate
- name: TNF, IL-1, and IL-6 Inhibitor Biologics
description: >-
Biologic DMARDs targeting TNF (etanercept, adalimumab), IL-1
(anakinra, canakinumab), and IL-6 (tocilizumab) are central to
treatment of JIA refractory to methotrexate. In systemic JIA, IL-1 and
IL-6 inhibitors are increasingly used as early therapy alongside
short-course glucocorticoids.
treatment_term:
preferred_term: biologic DMARD therapy
term:
id: NCIT:C15986
label: Pharmacotherapy
therapeutic_agent:
- preferred_term: etanercept
term:
id: NCIT:C2381
label: Etanercept
- preferred_term: adalimumab
term:
id: NCIT:C65216
label: Adalimumab
- preferred_term: anakinra
term:
id: NCIT:C38717
label: Anakinra
- preferred_term: canakinumab
term:
id: NCIT:C80971
label: Canakinumab
- preferred_term: tocilizumab
term:
id: NCIT:C84217
label: Tocilizumab
evidence:
- reference: PMID:39317417
reference_title: "EULAR/PReS recommendations for the diagnosis and management of Still's disease, comprising systemic juvenile idiopathic arthritis and adult-onset Still's disease."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The optimal therapeutic strategy relies on early use of interleukin (IL-1 or IL-6 inhibitors associated to short duration glucocorticoid (GC)."
explanation: EULAR/PReS recommendations directly support early IL-1 or IL-6 inhibitor therapy plus short-course glucocorticoids for systemic JIA / Still's disease.
- reference: PMID:38756937
reference_title: "Diagnosing and Treating Systemic Juvenile Idiopathic Arthritis and Adult-Onset Still's Disease as Part of the Still's Disease Continuum."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Recently, targeted therapies such as interleukin (IL)-1 and IL-6 inhibitors have become available for the treatment of sJIA and AOSD."
explanation: Supports availability of IL-1 and IL-6 inhibitor biologics for systemic JIA.
notes: >-
This entry is a root-level dismech record organising the ILAR categories
of juvenile idiopathic arthritis. Subtype-specific pathophysiology,
genetics, complications (notably uveitis in oligoarticular JIA and
macrophage activation syndrome in systemic JIA), and subtype-tailored
therapy are scoped as follow-up dismech entries.
disease_term:
preferred_term: juvenile idiopathic arthritis
term:
id: MONDO:0011429
label: juvenile idiopathic arthritis
No deep-research provider was invoked for this root-level entry. There
is no existing subtype dismech file for any ILAR category, so this
record was curated directly from the verified literature already
cached in references_cache/ that addresses JIA at the umbrella level.
Juvenile idiopathic arthritis (JIA, MONDO:0011429) is an umbrella
term for the chronic arthritides of childhood beginning before
16 years of age and persisting for at least six weeks, after exclusion
of infective, traumatic, malignant, and other defined causes. The
International League of Associations for Rheumatology (ILAR) criteria
stratify JIA into seven clinically distinct categories — oligoarticular,
polyarticular rheumatoid-factor-negative, polyarticular rheumatoid-
factor-positive, systemic, psoriatic, enthesitis-related, and
undifferentiated. PMID:29848426 ("Spectrum of Joint Deformities in
Children with Juvenile Idiopathic Arthritis") cites the ILAR
criteria as the operational basis for cohort enrolment in JIA studies.
Mechanistic axis: autoimmune vs autoinflammatory. PMID:29037901 frames the heterogeneity directly: "Juvenile Idiopathic Arthritis (JIA) is characterized with a variable pattern of articular involvement and systemic symptoms and, thus, it has been classified in several subtypes." Oligoarticular, polyarticular and RF-positive forms have an adaptive-autoimmune flavour with HLA-class-II linkage (HLA-DRB108, 01, *04 alleles depending on subset); systemic JIA is dominated by innate-immune activation with prominent IL-1 and IL-6 signalling.
PMID:38756937 and PMID:39317417 establish the Still's disease continuum
between systemic JIA and adult-onset Still's disease, and define the
modern therapeutic strategy: "The optimal therapeutic strategy relies
on early use of interleukin (IL-1 or IL-6 inhibitors associated to
short duration glucocorticoid (GC)." This is captured here as a
separate Systemic Autoinflammation (sJIA) pathophysiology node.
Synovial mechanism atomic decomposition. Per the PR review feedback,
the original single Synovial Inflammation node has been decomposed
into three atomic nodes connected via downstream edges:
Synovial Leukocyte Infiltration — T-cell and macrophage
recruitment to the synovial membrane (UBERON:0002018,
CL:0000235, GO:0006955 ABNORMAL).Synovial Hyperplasia — synoviocyte proliferation
(CL:0000214).Cytokine-Mediated Articular Damage — TNF / IL-1 / IL-6 -driven
cartilage and bone destruction (GO:0001816 INCREASED).Chronic anterior uveitis is the major extra-articular complication
of oligoarticular JIA and a leading cause of visual morbidity if
unscreened. It is now captured as a subtype-qualified phenotype
(HP:0012122 Anterior uveitis, temporality: CHRONIC,
subtype: Oligoarticular). Acute symptomatic uveitis also occurs in
enthesitis-related JIA but is not the same phenotype.
Treatment ladder. NSAIDs (MAXO:0000221), intra-articular and
short-course systemic glucocorticoids, methotrexate as the conventional
synthetic DMARD of first choice for polyarticular / extended-
oligoarticular JIA, and biologic DMARDs targeting TNF (etanercept,
adalimumab), IL-1 (anakinra, canakinumab), and IL-6 (tocilizumab),
with IL-1 / IL-6 inhibitors moving earlier in the treatment paradigm
for systemic JIA per the EULAR/PReS recommendations.