Juvenile psoriatic arthritis

A diagnosis of psoriatic arthritis is made in the presence of arthritis together with either a psoriatic rash or two of the following: dactylitis; nail pitting or onycholysis; psoriasis in a first-degree relative

• diagnosis may be challenging since skin manifestations appear few years later after articular involvement

In patients with juvenile psoriatic arthritis (1,2,3):

• incidence peaks at 2 to 4 years of age and then again after the age of 10 years
• articular involvement may vary e.g - from symmetrical small-joint arthritis to asymmetrical lower-extremity large-joint arthritis and finally may progress to polyarthritis mimicking seropositive rheumatoid arthritis.
• dactylitis (“sausage-like” fingers) is caused by arthritis of metacarpophalangeal, proximal interphalangeal and distal interphalangeal joints of one or more fingers
• features of enthesitis related arthritis may be present e.g. - enthesitis, sacroiliitis, spondylitis etc
• psoriatic plaques are usually present on the extensor sides of joints, haired skin, the umbilicus and the perineum
• nail changes are common e.g. - nail dystrophy, subungual hyperkeratosis and onycholysis
• psoriasis occurs in half of affected children but may not develop until later in the disease course (3)
• HLA-B27 is present in 10 to 12% of patients (3)

Reference:

• (1) Barut K, Adrovic A, Şahin S, Kasapçopur Ö. Juvenile Idiopathic Arthritis. Balkan Medical Journal. 2017;34(2):90-101.
• (2) Makay B, Unsal E, KasapcopurO. Juvenile idiopathic arthritis. World J Rheumatol. 2013; 3(3): 16-24
• (3) Sandborg CI et al. Juvenile Idiopathic Arthritis. NEJM 2025;393:162-174