Comparison of psoralen-UVB and psoralen-UVA photochemotherapy in the treatment of psoriasis

Background: PUVA treatment of psoriasis is usually given with broad-band fluorescent UVA lamps. Narrow-band UVB exposure after oral methoxsalen has been shown to achieve a greater therapeutic response in psoriasis than identical UVB exposure given without psoralen. Objective: The purpose of this study was to compare conventional PUVA with psoralen-UVB therapy in psoriasis. Methods: We studied 100 patients with plaque type psoriasis who were randomly selected to receive either conventional psoralen-UVA or psoralen-UVB treatment. Results: No significant difference was found between the two treatments in the proportion of patients whose skin cleared during treatment or in the number of exposures required for clearance of psoriasis. As expected, the cumulative UV dose for clearance was smaller in the group treated with UVB compared with those receiving UVA. Side effects and disease status at 3 months after the end of treatment were similar for the two groups. Conclusion: Psoralen-UVB treatment of psoriasis is as effective as conventional PUVA. The mechanism of psoralen-311 nm UVB action on psoriasis requires study to predict the longterm safety of this treatment.