Table 1: 2001 ILAR JIA Definitions and Exclusion Criteria 2

JIA Categories Definition ILAR Exclusion Criteria
1. Oligoarticular JIA,
Persistent and
Extended
Arthritis affecting four or fewer joints during the first 6 months of disease
Persistent oligoarthritis: Arthritis in four or fewer joints for the entire disease course
Extended oligoarthritis: Arthritis in five or more joints after the initial 6 months of disease
(1) Psoriasis in the patient or a history of psoriasis in a first-degree relative; OR
(2) Arthritis in an HLA-B27 male beginning after his sixth birthday; OR
(3) Two positive tests for RF obtained at least three months apart; OR
(4) HLA-Associated disease* in a first-degree relative; OR
(5) Systemic arthritis
2. RF-negative polyarticular JIA Arthritis affecting 5 or more joints during the first 6 months of disease, with an RF negative test (1) Psoriasis in the patient or a history of psoriasis in a first-degree relative; OR
(2) Arthritis in an HLA-B27 male beginning after his sixth birthday; OR
(3) Two positive tests for RF obtained at least three months apart; OR
(4) HLA-Associated disease* in a first-degree relative; OR
(5) Systemic arthritis
3. RF-positive polyarticular JIA Arthritis affecting 5 or more joints during the first 6 months of disease, with 2 or more positive tests for RF at least 3 months apart during the first 6 months of disease (1) Psoriasis in the patient or a history of psoriasis in a first-degree relative; OR
(2) Arthritis in an HLA-B27 male beginning after his sixth birthday; OR
(3) HLA-Associated disease* in a first-degree relative; OR
(4) Systemic arthritis
4. Systemic arthritis Arthritis in one or more joints with or preceded by fever of at least 2 weeks duration that is documented to be daily for at least 3 days, AND
Accompanied by one or more of the following:
     1. Evanescent erythematous rash
     2. Generalized lymph node enlargement
     3. Hepatomegaly and/or splenomegaly
     4. Serositis
(1) Psoriasis in the patient or a history of psoriasis in a first-degree relative; OR
(2) Arthritis in an HLA-B27 male beginning after his sixth birthday; OR
(3) Two positive tests for RF obtained at least three months apart; OR
(4) HLA-Associated disease* in a first-degree relative
5. Psoriatic arthritis Arthritis and psoriasis, or arthritis and at least 2 of the following:
     1. Dactylitis
     2. Nail pitting or onycholysis
     3. Psoriasis in a first-degree relative
(1) Arthritis in an HLA-B27 male beginning after his sixth birthday; OR
(2) Two positive tests for RF obtained at least three months apart; OR
(3) HLA-associated disease* in a first-degree relative; OR
(4) Systemic arthritis.
6. Enthesitis-related arthritis Arthritis and enthesitis, or arthritis or enthesitis with at least 2 of the following:
     1. Presence or a history of sacroiliac joint tenderness and/or inflammatory lumbosacral pain
     2. The presence of HLA-B27 antigen
     3. Onset of arthritis in a male over 6 years of age
     4. Acute anterior uveitis
     5. History of ankylosing spondylitis, enthesitis related arthritis, sacroiliitis with inflammatory bowel disease, Reiter’s syndrome, or acute anterior uveitis in a first-degree relative
(1) Psoriasis in the patient or a history of psoriasis in a first-degree relative; OR
(2) Arthritis in an HLA-B27 male beginning after his sixth birthday; OR
(3) Two positive tests for RF obtained at least three months apart; OR
(4) Arthritis that fits 2 or more categories
7. Undifferentiated arthritis Arthritis that fulfills criteria in no category or in 2 or more of the above categories

Legend: ILAR = International League of Associations for Rheumatology
RF = Rheumatoid Factor
HLA = Human Leukocyte Allele
ERA = Enthesitis-Related Arthritis
*HLA-associated disease includes ankylosing spondylitis, ERA, sacroiliitis with inflammatory bowel disease, reactive arthritis, or acute anterior uveitis