Pityriasis rubra pilaris

Pityriasis rubra pilaris (PRP) is a rare and chronic skin disorder that often has a sudden onset. 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 no known cause or cure.

It was first described by Marie-Guillaume-Alphonse Devergie in 1856, and the condition is also known as Devergie's disease.

Classification
Dr. W.A.D. Griffiths, from Great Britain, classified six forms of PRP in the early 1980s. At this time, the causes of PRP are still unknown and symptoms can be difficult to diagnose. Frequently, more than one medical professional will be consulted before an accurate PRP diagnosis is made.

Dermatologists have identified both an acquired form and an inherited form (familial) of PRP and have described them in medical journals. The acquired form usually shows a spontaneous or gradual remission of symptoms within several years although long-term symptoms may continue for years. The inherited form starts early in childhood with persistent long-term symptoms into adulthood.

Although most people who develop PRP are over age 50, individuals of any age, race, and nationality can be affected. Women and men seem to be equally affected.