Efficacy of bath psoralen plus ultraviolet A (PUVA) vs. system PUVA in psoriasis: a prospective, open, randomized, multicentre study

Summary Background Plaque psoriasis is an inflammatory disease affecting approximately 2% of the population. The clinical hallmarks of psoriasis are sharply demarcated, erythematous plaques with thick scales. Photochemotherapy (psoralen plus ultraviolet A, PUVA) is one of the most effective therapies of psoriasis. The photosensitizer 8‐methoxypsoralen (8‐MOP) can be applied either orally (system PUVA) or topically in a warm water bath (bath PUVA). Objectives To compare bath PUVA and system PUVA in the treatment of plaque psoriasis. Methods This was a randomized, open, prospective, multicentre trial. We included 74 patients with moderate‐to‐severe plaque psoriasis during a 6‐week treatment and a 4‐week follow‐up period. Of the patients enrolled in the study, 38 received bath PUVA and 36 system PUVA. Results Both treatment modalities significantly reduced the median Psoriasis Area and Severity Index (PASI) score in the intention‐to‐treat population. Within 6 weeks bath PUVA reduced the median PASI by 74% (16·4 to 4·2) while system PUVA did so by 62% (15·3 to 5·8). The difference between the two modalities was not significant with regard to treatment efficacy (P = 0·389). Conclusion There is no difference between bath PUVA and system PUVA in the treatment of psoriasis. What's already known about this topic? System photochemotherapy (oral psoralen plus ultraviolet A, system PUVA) is known to be highly effective in psoriasis. What does this study add? There was no significant difference between bath PUVA and system PUVA in treating psoriasis in a prospective, randomized, multicentre trial.