Targeted UV-B Phototherapy for Plaque-type Psoriasis

Objective: To determine whether targeted UV-B phototherapy is efficacious and safe in the treatment of localized psoriasis and whether there is a dose-response relationship. Design: Randomized, evaluator-blind, controlled study. Setting: Dermatology clinic in a large university-based hospital in Bangkok, Thailand. Patients: Fourteen patients with stable, localized, plaque-type psoriasis. Interventions: Patients were randomized to receive different fluences of targeted UV-B phototherapy 3 times weekly based on predetermined minimal erythema doses (MEDs). Treatment fluences were constant throughout the study period of 4 weeks. Follow-up was carried out until lesions returned to original state. Main Outcome Measures: Modified psoriasis area and severity index. Results: All fluences of UV-B produced some clinical improvement and were very well tolerated. Fluences ranging from 1 to 6 multiples of MEDs resulted in clearance of lesions in some patients with 6 MEDs producing clearance in 77% of patients. The number of treatments required to clear psoriatic lesions when 2 to 6 MEDs were used was 5.0 to 6.1 treatments. The only adverse events observed were erythema, which was asymptomatic in most subjects, and hyperpigmentation. Conclusions: Incoherent, targeted IJV-B phototherapy is a safe and efficacious treatment modality for localized psoriasis. Its value in other UV-B responsive conditions should be further investigated.