Occlusion enhances the efficacy of topical calcipotriol in the treatment of psoriasis vulgaris.
Forty-eight patients with symmetrical chronic plaque psoriasis affecting the limbs were recruited for a single-blind right/left within patient study to assess the effect of combining occlusion with topical calcipotriol. Subjects were randomized into two groups. Sites of similar severity on opposing limbs were selected as target areas. The first (group A) treated one side with calcipotriol alone and the opposite side with calcipotriol plus occlusion. The second (group B) treated one side with placebo plus occlusion and the opposite side with calcipotriol plus occlusion. In group A the mean improvements were 40% (P < 0.001) for calcipotriol alone and 61% (P < 0.001) for calcipotriol plus occlusion. In group B, occlusion plus calcipotriol resulted in a mean 62% improvement (P < 0.001) while occlusion plus placebo produced no significant change. The combination of calcipotriol plus occlusion was significantly better than calcipotriol alone (P < 0.005). The results indicate that occlusion improves the response to calcipotriol by enhancing its penetration. Indices of calcium metabolism remained unchanged throughout the study.