Topical treatment of pityriasis rubra pilaris with calcipotriol.

From a clinical, histological and therapeutic point of view, psoriasis and pityriasis rubra pilaris share important characteristics. Recently, calcipotriol has been shown to be an effective treatment in psoriasis, and we report three patients with pityriasis rubra pilaris who showed a favourable response to topical therapy with calcipotriol. In one case, analysis of markers for epidermal growth, differentiation and inflammation revealed reduction of suprabasal expression of keratin 16, and the number of T lymphocytes, monocytes and macrophages. It is of interest that a reduction of the recruitment of cycling epidermal cells, which is a consistent response pattern during treatment of psoriasis, was not observed during treatment of pityriasis rubra pilaris.