Pityriasis Rubra Pilaris

Abstract Pityriasis rubra pilaris represents a group of rare inflammatory skin disorders of unknown aetiopathology sharing common clinical and histopathological features. The disease is characterised by the appearance of hyperkeratotic follicular papules, which tend to coalesce to diffuse pink or red plaques, and a yellowish palmoplantar keratoderma. It may progress to erythroderma with characteristic distinct areas of uninvolved skin, the so‐called ‘islands of sparing’. Based on its age of onset, clinical presentation and prognosis, pityriasis rubra pilaris has been classified into distinct subtypes.