Prevalence of ultrasound and clinical findings suggestive of inflammatory arthritis in children with skin psoriasis

Objective: To evaluate the prevalence of clinical and ultrasound (grey-scale and Doppler) abnormalities in joints, periarticular structures and nails of children affected by skin psoriasis (PsO). Methods: Cross-sectional study including consecutive children affected by PsO. A systematic clinical and ultrasound evaluation of joints, entheses, tendons and nails were performed by independent examiners blinded to each other assessment. Results: 57 Children: 26 girls (46%), mean age of 9 ± 4 years, divided into two groups, asymptomatic (Asy, 42 children) and symptomatic (Sy, 15 children) according to musculoskeletal pain. Differences were observed between the two groups in relation to age (9 ± 3 in Asy vs 11 ± 4 yrs in Sy, p< 0.05), PsO duration (2.4 ± 2.4 vs 5.4 ± 3.9 yrs, p< 0.001), systemic treatment (23 [54.8%] vs 2 [13.3%], p< 0.01), tender joint count (0 vs 12 children [80%], p< 0.001), swollen joint count (0 vs 3 [20%], p< 0.01) and entheseal pain (0 vs 10 [66.7%], p< 0.001). Ultrasound evaluation showed statistically significant differences between Asy and Sy groups for the presence of ultrasound abnormalities (16/42 [38%] vs 12/15 [80%]), synovitis (1/42 [2%] vs 4/15 [25%]) and enthesitis (4/42 [9.5%] vs 5/15 [33%]). Three children in the Sy group were classified with juvenile psoriatic arthritis (JPsA). Conclusions: Ultrasound abnormalities were higher in the Sy group with synovitis and enthesitis as the most prevalent findings. Asy patients were more frequently under systemic treatment. Ultrasound and a systematic clinical evaluation are useful tools for detecting subclinical JPsA in children with PsO and musculoskeletal symptoms.