» Pasteurized Cream
a dairy product composed of the higher-fat layer skimmed from the top of raw milk before homogenization, then heat-treated (pasteurized) to destroy bacteria.

» Petroleum
an oily, flammable, liquid solution of hydrocarbons occurring naturally in certain geological formations which, when distilled, is often used as a base for ointments to treat various skin conditions (see Petroleum Jelly).

» Petroleum Jelly
a greasy, jellylike substance consisting of a mixture of semisolid hydrocarbons obtained from petroleum, often used as a base for ointments to treat various skin conditions; does not penetrate the surface of the skin and does not replace skin moisture.

» Phototherapy
treatment with light.

» Plaque
an abnormal patch on the skin; in the case of Psoriasis, usually evidenced by silvery scales, often joined together to involve extensive areas of skin.

» Poison Ivy, Poison Oak, Poison Sumac
Skin inflammation resulting from contact with the oil Urushiol produced by the Poison Ivy, Poison Oak and Poison Sumac plant. Contact with Urushiol causes an immune reaction, producing redness, itching, and blistering of the skin. It is found in the resinous sap material produced by the leaves, fruit, stem, and bark of these plants.

» Pruritus
itch

» Psoriasis
a chronic skin disorder characterized by inflammation and frequent episodes of redness, itching and thick, dry, silvery scales on the skin. Psoriasis is probably related to an inflammatory response in which the immune system mistakenly targets the body's own cells, resulting in new skin cells being produced about 8 times faster than normal – over several days instead of a month – but the rate at which old cells slough off is unchanged. This causes a build-up of dead skin cells and formation of thick patches, or plaques, of red sores (lesions) covered with flakey , silvery-white dead skin cells (scales).