Criteria for juvenile arthritis: onset before 16th birthday
Criteria for the diagnosis of psoriatic arthritis - all of the following:
(1) arthritis
(2) one of the following:
(2a) psoriasis
(2b) at least 2 of the following:
(2b1) dactylitis
(2b2) pitting or onycholysis (psoriatic nail abnormalities)
(2b3) family history of psoriasis in at least 1 first degree relative, confirmed by a dermatologist
(3) none of the following:
(3a) presence of rheumatoid factor (RF)
(3b) presence of a systemic arthritis
Additional descriptors:
(1) age of onset for psoriasis
(2) age of onset for arthritis
(3) pattern of arthritis at 6 months after disease onset (large vs small joint, limb predominance, specific joint)
(4) oligoarthritis vs polyarthritis
(5) presence of ANA
(6) anterior uveitis
(7) HLA antigens
