Psoriatic arthritis develops in a small proportion of children and young adults with psoriasis, with obesity, nail involvement and male predominance more common among affected individuals, a registry analysis led by researchers in the Netherlands has found.

The prospective registry analysis, published in the Journal of Psoriasis and Psoriatic Arthritis, investigated the timing, clinical features and incidence of juvenile or adult-onset psoriatic arthritis in a large cohort of patients with paediatric-onset psoriasis.

Data were analysed on 717 children and young adults enrolled in the Dutch real-world psoriasis registry Child-CAPTURE, which includes patients diagnosed with psoriasis before age 18, with follow-up into young adulthood.

Participants had a cumulative observation period of 2,850 years. The majority were female (60.1%), and the median age at psoriasis diagnosis was eight years.

Clinical assessments included psoriasis severity, body mass index, body surface area involvement, nail involvement and subsequent development of arthritis.

Juvenile psoriatic arthritis was defined as having a diagnosis before 18 years of age using International League of Associations for Rheumatology criteria, while adult-onset diagnosed from age 18 onwards was classified according to ClASsification criteria for Psoriatic Arthritis (CASPAR).

Predictors of psoriatic arthritis development

Among the 717 patients, 15 developed juvenile (n=8) or adult psoriatic arthritis (n=7) during follow-up. Kaplan-Meier analysis estimated a cumulative incidence of arthritis of 2.8% within 10 years of psoriasis diagnosis.

The median interval between psoriasis onset and arthritis diagnosis was 4.8 years. Patients who developed arthritis had a median age of 12 years at psoriasis diagnosis and 17.3 years at arthritis onset.

At the time of arthritis diagnosis, median Psoriasis Area and Severity Index scores were lower than at registry inclusion, falling from 6.3 to 3.9. Median body surface area involvement also decreased from 6.6% to 2.5%.

A greater percentage of patients who developed arthritis were male (66.7% vs 39.9% in the overall cohort). Obesity was also more common among those who developed arthritis, with 30.8% classified as obese compared with 6.7% in the entire cohort.

Nail involvement at baseline was observed in 40.0% of patients who later developed juvenile or adult psoriatic arthritis, compared with 18.0% of the total cohort.

Supporting earlier recognition of arthritis in paediatric psoriasis

The authors noted that the findings align with previous literature that identified obesity and nail disease as possible predictors of psoriatic arthritis development in children with psoriasis. They also highlighted that it occurred despite clinically controlled skin disease in several patients.

However, several limitations were acknowledged, including the relatively low number of arthritis events and the possibility of under-reporting as the Child-CAPTURE registry was not specifically designed to identify arthritis outcomes.

Differences in follow-up duration between the overall cohort and patients who developed arthritis may also have influenced findings, although Kaplan-Meier analysis could help to address this.

Despite these limitations, the authors concluded that while the overall incidence of children with psoriasis developing juvenile or adult psoriatic arthritis appears low, awareness should be heightened among male patients and when obesity and/or nail involvement are present.

They added that these findings could enhance early detection of arthritis in paediatric psoriasis and support efforts to refine the classification criteria for juvenile psoriatic arthritis.

Reference
Al-Gawahiri M et al. Development of arthritis in a large real-world cohort of patients with pediatric onset psoriasis. J Psoriasis Psoriatic Arthritis 2026; Apr 25: 24755303261446205.