Pityriasis

Pityriasis commonly refers to flaking (or scaling) of the skin. The word comes from the Greek πίτυρον 'bran'.

Classification
Types include:
 * Pityriasis alba, dry, fine-scaled, pale patches on the face
 * Pityriasis lichenoides chronica, caused by a hypersensitivity reaction to infectious agents
 * Pityriasis lichenoides et varioliformis acuta, a disease of the immune system
 * Pityriasis rosea, a type of skin rash
 * Pityriasis circinata,
 * Pityriasis rubra pilaris, reddish-orange patches (Latin: rubra) on the skin
 * Pityriasis versicolor, a skin eruption on the trunk and proximal extremities, usually caused by a fungus
 * Dandruff, historically called Pityriasis capitis
 * Pityriasis amiantacea, condition of the scalp in which thick tenaciously adherent scale infiltrates and surrounds the base of a group of scalp hairs