Development of Arthritis in a Large Real-World Cohort of Patients With Pediatric Onset Psoriasis

Background: Early identification and treatment of psoriatic arthritis (PsA) among patients with psoriasis is important to prevent joint damage. Insights in arthritis onset and the associated clinical factors among pediatric and young adult patients with psoriasis is scarce. Objectives: To describe pediatric patients with psoriasis who subsequently developed psoriatic arthritis at pediatric age or in young adulthood (JPsA/PsA). We focused on clinical features and timing of onset, and compared clinical features to characteristics of a large cohort of pediatric psoriasis patients. Methods: Data on patients with pediatric onset of psoriasis were obtained from the prospective, daily practice, ChildCAPTURE registry. Descriptive statistics were used. ILAR and CASPAR criteria were used for classification of JPsA and PsA, respectively. The time to JPsA/PsA diagnosis following psoriasis onset was analyzed using Kaplan-Meier survival analysis. Results: Among 717 pediatric and young adult patients with psoriasis, 15 (2.1%) developed arthritis, of which 8 patients before the age of 18 years (1.1%, JPsA) and 7 patients in young adulthood (1.0%, PsA), with an estimated incidence of 2.8% within 10 years after psoriasis diagnosis. The median interval between psoriasis onset and JPsA/PsA development was 4.8 years. Male sex, obesity, and nail involvement were common clinical features of patients developing JPsA/PsA, and these were observed more frequently compared to the total pediatric psoriasis cohort. Conclusion: The incidence of JPsA/PsA among patients with pediatric onset of psoriasis is low. If the clinical features male sex, obesity and nail involvement are present, extra awareness for the development of JPsA/PsA is warranted.