Pityriasis rubra pilaris (Q43925)

Pityriasis rubra pilaris (PRP) is the name given to a group of clinically similar papulosquamous dermatoses of unknown aetiology. They initially present with erythematous, hyperkeratotic perifollicular papules, which tend to coalesce into plaques, but may progress to erythroderma, particularly in adults. The distribution, age of onset and speed of onset differ markedly between patients and these differences have been used to classify PRP into a number of clinically distinct subtypes.