The severity of nail disease, the presence of arthralgia and fatigue are predictors of development of psoriatic arthritis (PsA) in patients with psoriasis (Pso). In children, little is known about the musculoskeletal (MSK) impairment in patients with Pso and its effect on health-related quality of life (HRQoL).
To determine the frequencies of pain and MSK inflammation (i.e., arthritis, enthesitis, and sacroiliitis) among children and adolescents with Pso and its relationship to HRQoL and fatigue.
Pediatric patients with Pso underwent a rheumatologic physical examination to evaluate synovitis, enthesalgia, sacroiliac joint (SIJ) pain and tender points of fibromyalgia. The core set of domains recommended by the GRAPPA - OMERACT to be measured in PsA studies was assessed. Ultrasound (US) was performed in clinical cases of enthesitis, and magnetic resonance imaging (MRI) was performed in cases of SIJ pain.
Forty-three participants (10 ± 2.9 years old) were evaluated. Pain on palpation of the entheses was observed in 10 (23.2%) patients and pain on SIJ palpation was observed in 3 (7%). No patient presented with synovitis; one presented with enthesitis on US, but MRI did not confirm sacroiliitis in any case. Patients with MSK pain had greater skin disease severity (PASI 5.4 vs. 2, p <  0.01), worse fatigue, and lower HRQoL scores on all instruments used. The estimated risk of HRQoL impairment was eight times higher in the presence of MSK pain, which was an independent predictive factor. With a NAPSI greater than 30, the probability of pain was greater than 80%.
MSK pain is frequent among children with Pso, related to the severity of skin and nail disease, and negatively affects HRQoL. The typically used complementary exams might not detect the inflammatory process caused by Pso.