Psoriasis is characterized by red, elevated plaques that are often overlaid with thick, silvery white scales. The most commonly affected areas are the elbows, knees, scalp, lower back, and genitalia. Some people have psoriasis on their hands and feet. A condition called inverse psoriasis manifests plaques in folded areas, such as in the armpits and groin.
Psoriasis can be physically and emotionally disabling.
Although the liklihood for familial transmission may not seem significant, there is a definite genetic predisposition for psoriasis. The exact mode of inheritance is complex and variable. Most people with psoriasis report that no particular event or illness preceded or brought about their condition, but there are several well-known triggers, such as stress, strep infection, and some medications. Typically, psoriasis lesions are round, red, and have sharply defined edges with an overlying silvery white scale. These plaques usually begin as small spots that progressively involve very large areas.