Comparison of topical 8‐methoxypsoralen and narrowband ultraviolet B with narrowband ultraviolet B alone in treatment‐resistant sites in plaque‐type psoriasis: a placebo‐controlled study

SummaryBackground Combination of topical methoxsalen and narrowband ultraviolet B (NBUVB) was shown to be more effective than NBUVB alone in treating plaque-type psoriasis. Objective To find out whether topical methoxsalen and NBUVB had any benefit in induction of remission on treatment-resistant plaques of psoriasis on the legs in comparison with NBUVB alone. Methods Ten patients were included. Two symmetric lesions with similar Psoriasis Severity Index score on the lower legs were randomly assigned to be treated with cold cream as placebo or 0.1% 8-methoxypsoralen (8MOP) cream 15 min before phototherapy with NBUVB. Phototherapy was given three times per week for up to three months. Severity scores were recorded each week and side effects were observed before each session. Results Significant decrease in the severity score was observed in both groups (P-value < 0.001), but none of the lesions cleared completely at the end of the study. The decrease of the score in the 8MOP arm was greater than the control arm; however, the difference was not significant. The only side effect was pigmentation that occurred in all of the 8MOP-treated patients after 2 weeks. Conclusion We could not confirm any significant benefit of topical methoxsalen and NBUVB in comparison to NBUVB alone in treating resistant plaques of psoriasis on the legs.