Pediatric Psoriasis with or without Arthritis: Does It Make a Difference?

Background: Psoriasis and psoriatic arthritis can present simultaneously or separately in children and may pose a diagnostic challenge. Objective: To compare the dermatological manifestations in pediatric psoriatic patients with and without arthritis. Methods: A retrospective case-control study of psoriatic patients ≤ 18 years old at Sheba Medical Center was conducted between 2011 and 2021. Patients with psoriatic arthritis versus psoriasis-only were compared according to body surface area (BSA) involvement, cutaneous distribution, severity of skin disease, response to treatment and related side effects. Results: The study cohort included 29 psoriatic arthritis and 64 psoriasis-only patients matched by age and sex. The psoriasis-only group had a significantly higher mean BSA (19.7%, SD ± 18.7) than the psoriatic arthritis group (6.1%, SD ± 11.4), (p = 0.029). The skin distribution differed with the psoriasis group showing more involvement of the extremities, scalp, trunk, and genitals. Both groups primarily experienced partial responses to methotrexate, whereas the psoriasis group mainly saw complete responses to biologics. Adverse events were rare, with a higher incidence in the psoriasis group. Conclusion: This retrospective study highlights the differences in cutaneous disease characteristics, severity, and treatment response in pediatric patients with psoriasis and psoriatic arthritis, providing valuable insights for diagnosis and disease course in the pediatric population.