Pityriasis rubra pilaris (also known as "Devergie's disease", "lichen ruber acuminatus", and "lichen ruber pilaris") refers to a group of chronic disorders characterized by reddish orange, scaling plaques and keratotic follicular papules. Symptoms may include reddish-orange patches (Latin: rubra) on the skin, severe flaking (Latin: pityriasis), uncomfortable itching, thickening of the skin on the feet and hands, and thickened bumps around hair follicles (Latin: pilus for hair). For some, early symptoms may also include generalized swelling of the legs, feet and other parts of the body. PRP has a varied clinical progression and a varied rate of improvement. There is currently no known cause or cure for PRP.
It was first described by Marie-Guillaume-Alphonse Devergie in 1856, and the condition is also known as Devergie's disease.