Psoriasis is a chronic, autoimmune disease that appears on the skin. It occurs when the immune system sends out faulty signals that speed up the growth cycle of skin cells. Psoriasis is not contagious.
There are five types of psoriasis. The most common form, plaque psoriasis, appears as raised, red patches covered with a silvery white buildup of dead skin cells. Psoriasis can occur on any part of the body and is associated with other serious health conditions, such as diabetes, heart disease and depression.
Psoriasis is the most common autoimmune disease in the U.S. As many as 7.5 million Americans have psoriasis.
Types of psoriasis
Psoriasis appears in a variety of forms with distinct characteristics. Typically, an individual has only one type of psoriasis at a time. Learn more about the types of psoriasis »
Psoriasis can show up anywhere—on the eyelids, ears, mouth and lips, skin folds, hands and feet, and nails. The skin at each of these sites is different and requires different treatments. Read more on where psoriasis shows up »
Researchers believe that for a person to develop psoriasis, the individual must have a combination of the genes that cause psoriasis and be exposed to specific external factors known as "triggers." Read more about what causes psoriasis »
Conception and pregnancy
In general, psoriasis does not affect the male or female reproductive systems. However, many psoriasis treatments require special precautions before and during pregnancy. Learn more about psoriasis and pregnancy »