Pityriasis rubra pilaris response to 13-cis-retinoic acid (isotretinoin).

Forty-five patients with pityriasis rubra pilaris were treated with oral 13-cis-retinoic acid (isotretinoin). There was marked improvement in the degree of erythema, in duration, and scaling noted within 4 weeks. Remission or maintained improvement persisted after stopping therapy in many of the patients. The drug is a significant addition to the therapeutic armamentarium in this difficult-to-treat disease.