Psoriasis is a skin condition characterized by dry, whitish patches on the skin.
Normally, new skin cells rise to the surface of the skin once a month; the old surface skin cells die and fall off while the new cells are moving to the surface. In people who have psoriasis, the new cells move to the surface so rapidly that the dead cells build up on the surface.
Some people have mild cases of psoriasis. Others have extensive cases that affect multiple parts of the body.