The International League of Associations for Rheumatology (ILAR) has listed criteria for the diagnosis of idiopathic juvenile oligoarthritis. The original criteria proposed in Santiago, Chile, in 1994 were modified at Durban, South Africa, in 1997.
Criteria for juvenile arthritis:
(1) onset before 16th birthday
(2) duration of >= 6 weeks
Criteria for the diagnosis of oligoarthritis - all of the following:
(1) arthritis in 1 to 4 joints throughout the disease course
(2) none of the following:
(2a) presence of rheumatoid factor (RF)
(2b) presence of a systemic arthritis
(2c) presence of psoriasis in at least 1 first or second degree relative, confirmed by a dermatologist
(2d) presence of HLA-B27 associated disease in at least 1 first or second degree relative, confirmed by a physician
(2e) HLA-B27 positive and male with onset of arthritis after 8 years of age (see juvenile enthesitis arthritis)
Subcategories:
(1) persistent - affects no more than 4 joints throughout the disease course
(2) extended - affects a cumulative total of 5 or more joints after the first 6 months of illness
Additional descriptors:
(1) age of onset of arthritis
(2) pattern of arthritis at 6 months after disease onset (large vs small joint, limb predominance, specific joint, symmetry)
(3) presence of ANA
(4) anterior uveitis (acute or chronic)
(5) HLA class I and II predisposing or protective alleles
