What is psoriasis?
Psoriasis is a chronic skin condition in which skin cells develop and flake off more rapidly than normal, causing dry and red areas of skin that are covered with silvery scaling. These areas of dry skin are called plaques. They can be the size of a thumbnail or cover large areas, such as the back or buttocks, and can occur anywhere on the skin. Psoriasis plaques are most likely to appear on the scalp, elbows, knees, trunk, buttocks, and back.
Although it's not fully known what causes psoriasis, it's thought to be related to the body's immune system. One type of white blood cell called the T-lymphocyte, a cell that normally travels through the body to detect and fight foreign diseases and substances, attacks healthy skin cells instead. This attack is what causes an in an increased production of both skin cells, leading to the plague growth on the skin from overactive skin production. Psoriasis also tends to run in families and is more likely to affect people with white skin. Psoriasis can affect people of all ages, but typically first appears in youth to middle age. It is not contagious.
Psoriasis affects 1 to 3% of people living in the U.S. It is characterized by periods of remission with flare-ups in which symptoms worsen. It's believed that sunburn or other injury to the skin, certain medications, and other factors can cause flare-ups. Although psoriasis is a chronic disease with no cure, early treatment may help keep it from becoming more severe.