Comparison of phototherapy two times and four times a week with low doses of narrow‐band ultraviolet B in Asian patients with psoriasis

Abstract

Background/Aims: The optimum narrow‐band (TL‐01) ultraviolet (UV) B weekly treatment frequency for psoriasis has yet to be defined, especially in Asian patients with TL‐01. Our purpose was to compare 2× weekly and 4× weekly therapy with narrow‐band UVB at low doses for psoriasis vulgaris.Methods: Sixty‐nine patients with moderately severe psoriasis were recruited and allocated to the 2× weekly or 4× weekly treatment group. The patients were treated with a new protocol using low doses of narrow‐band UVB with varied exposure increments. Outcomes were evaluated by means of Psoriasis Area and Severity Index (PASI) scores, time (weeks), cumulative UVB dose and number of treatments to clearance.Results: No significant difference was found between the two regimens in the PASI score at the end of treatment, in the proportion of patients whose skin cleared during treatment and in the time to clearance (8 weeks). Those who completed treatment achieved clearance after a median of 16 exposures with 2× weekly treatment compared with 32 exposures with 4× weekly treatment (P=0.0304), and 12.5 minimal erythema dose multiples (MEDs) compared with 39.7 MEDs (P=0.0470). Acute side effects of the treatment were similar for the two groups (P=0.8462).Conclusion: For skin phototype III‐V populations, a greater long‐term risk is expected, connected with the higher cumulative UVB dose and number of exposures required in the 4× weekly group. Therefore, 4× weekly phototherapy will no longer be used for psoriasis.