True about Pityriasis rubra pilaris?

Pityriasis rubra pilaris Definition: Heterogeneous group of disorders that have circumscribed follicular keratoses, branny scale and an orange-red erythema. C/F: It shows an equal sex incidence. Bimodal age distribution with peaks in the first and fifth decades. Lesion: Erythematous follicular hyperkeratosis giving a 'nutmeg grater' appearancee. Mainly seen over the elbows, knees, wrists and back of fingers. Pt. presents with well defined salmon red or orange-red dry scaly plaques. Islands of normal skin are present, the so called 'islands of sparing'. Associated disorders: Leukaemia Metastatic carcinoma Treatment: Topical : Coicosteroids + Salicylic acid (if thickening). In the erythrodermic phase: Acitretin or Isotretinoin are used.