PD01 Targeted phototherapy with monochromatic excimer light is not efficacious in the management of residual vitiligo patches following whole-body narrowband ultraviolet B light therapy: an open-label, prospective study

Abstract

Complete repigmentation in vitiligo is difficult even after adequate whole-body narrowband ultraviolet B (NB-UVB) therapy. The aim of our prospective study was to evaluate the efficacy of 16 weeks of twice-weekly monochromatic excimer light (MEL) therapy for residual vitiligo patches (≤ 5% body surface area) following adequate NB-UVB therapy (≥ 80 sessions or no further repigmentation after 12 additional sessions). Disease extent and response were assessed using the Lund and Browder score, Investigator’s Global Assessment (IGA) and Patient Global Assessment (PGA), and quality-of-life measures (Vitiligo Impact Scale-22, VIS-22). Dermoscopic features of residual patches were recorded and correlated with outcomes. Thirty patients were enrolled (median age 36.5 years; 26 female and 4 male), with 2 lost to follow-up. After 16 weeks of MEL therapy, only two patients (7%) showed mild repigmentation (1–25%), and none showed moderate (25–50%) or significant repigmentation (> 50%). Of 472 treated residual patches, 52 (11%) showed repigmentation, mostly on the lower limb (38%) and trunk (37%). Overall, 63% of patches (33 of 52) showed mild repigmentation, 12 (23%) showed moderate repigmentation, 6 (12%) showed > 50% repigmentation and 1 one patch (2%) achieved complete repigmentation (P = 0.95). The median Lund and Browder score was 2.56 at baseline, slightly decreasing at 4 weeks (2.39; P = 0.09) then rising to 3.14 by 16 weeks. The mean PGA increased from 2.08 (SD 4.65) to 6.83 (12.1) (P < 0.01). VIS-22 scores were unchanged (median 19.5 at baseline and 16 weeks; P = 0.26). Dermoscopic features such as marginal pigmentation, indeterminate margins, complete pigment network, hypopigmentation, perilesional hyperpigmentation, polka dots and absence of leucotrichia showed higher mean IGA, although not significantly. Adverse effects included transient erythema (80%), itching (30%), perilesional hyperpigmentation (17%) and scaling or xerosis (10%). Loss of prior NB-UVB repigmentation occurred in 37%. In conclusion, MEL provided minimal repigmentation for residual vitiligo patches after NB-UVB therapy, and no meaningful quality-of-life improvement.