Real-World Predictors of Relapse-Free Duration After Narrowband UVB in Pediatric Psoriasis: A Multicenter Study.

Abstract

Background: Narrowband ultraviolet B (NB-UVB) phototherapy is a well-established, safe, and effective treatment for pediatric psoriasis; however, relapse after therapy remains a major challenge. Data regarding prognostic factors influencing remission durability in children are limited.

Objectives: To evaluate treatment response, relapse patterns, and predictors of relapse-free duration in pediatric psoriasis patients treated with NB-UVB phototherapy, with a particular focus on concomitant topical corticosteroid and calcipotriol use, and clinical features such as nail involvement.

Methods: This multicenter retrospective study included 114 pediatric psoriasis patients treated with NB-UVB across six tertiary dermatology centers in Türkiye. Treatment response was defined as ≥ 75% improvement in the Psoriasis Area and Severity Index (PASI75). Relapse was defined as clinically significant recurrence requiring renewed NB-UVB or systemic therapy within 6 months after treatment completion. Multivariable linear regression identified independent predictors of relapse-free duration.

Results: Of 114 patients (mean age 12.2 ± 3.6 years; 52.6% male), 65.8% achieved PASI75 and 42.1% PASI90. Responders received significantly higher cumulative doses and more sessions than nonresponders (p < 0.001). Relapse occurred in 24.0% of responders within 6 months. In multivariate analysis, concomitant topical corticosteroid use independently predicted longer relapse-free duration (β = 0.578, p = 0.001), whereas nail involvement predicted shorter remission (β = -0.520, p = 0.002). Topical calcipotriol and disease subtype were not significant predictors. NB-UVB was well tolerated, with mild erythema and pruritus as the most frequent adverse events (16.7%).

Conclusion: NB-UVB phototherapy provides high efficacy and an acceptable safety profile in pediatric psoriasis. Concomitant topical corticosteroid use may prolong remission, while nail involvement identifies patients at higher relapse risk, supporting closer monitoring and individualized follow-up and maintenance strategies.