[Pityriasis rubra pilaris].

Pityriasis rubra pilaris is a rare heterogeneous disorder characterized by follicular keratosis, perifollicular erythema and palmoplantar hyperkeratosis. The aetiology is still unknown. In the majority of cases some triggering factors are found such as trauma or bacterial infection, possibly on a predisposed condition. In other cases, some immunological disorders are associated, and in familial cases a genetic disorder of keratinization has been suggested. The evolution is variable according to the clinical type. The treatment is not well defined, and there is a lack of clinical trials. The best results however are obtained with oral retinoids, methotrexate or ciclosporine as alternative therapy. New TNF inhibitors and anti-IL-12/23 showed a good result and could be have interest in the future.