The International League of Associations for Rheumatology (ILAR) has listed criteria for the diagnosis of idiopathic juvenile polyarthritis 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 polyarthritis - all of the following:
(1) arthritis in 5 or more joints during the first 6 months of disease
(2) absence of systemic arthritis
Categories:
(1) rheumatoid factor positive
(1) rheumatoid factor negative (negative on 2 occasions at least 3 months apart)
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) immunogenetic characteristics
