Psoriasis is an autoimmune disease that causes raised, red, scaly patches to appear on the skin.
It typically affects the outside of the elbows, knees, or scalp, though it can appear on any location. Some people report that psoriasis is itchy, burns and stings. Psoriasis is associated with other serious health conditions, such as diabetes, heart disease, arthritis, and depression.
While scientists do not know what exactly causes psoriasis, we do know that the immune system and genetics play major roles in its development. Usually, something triggers psoriasis to flare. The skin cells in people with psoriasis grow at an abnormally fast rate, which causes the buildup of psoriasis lesions.
Psoriasis is not contagious. It is not something you can "catch" or that others can catch from you. Psoriasis lesions are not infectious.
There are five types of psoriasis. Learning more about your type of psoriasis will help you determine the best treatment for you.
1. Plaque psoriasis is the most common form of the disease and appears as raised, red patches covered with a silvery white buildup of dead skin cells. These patches or plaques most often show up on the scalp, knees, elbows and lower back. They are often itchy and painful, and they can crack and bleed.
2. Guttate [GUH-tate] psoriasis is a form of psoriasis that appears as small, dot-like lesions. Guttate psoriasis often starts in childhood or young adulthood, and can be triggered by a strep infection. This is the second-most common type of psoriasis, after plaque psoriasis. About 10 percent of people who get psoriasis develop Guttate psoriasis.
3. Inverse psoriasis shows up as very red lesions in body folds, such as behind the knee, under the arm or in the groin. It may appear smooth and shiny. Many people have another type of psoriasis elsewhere on the body at the same time.
4. Pustular [PUHS-choo-lar] psoriasis in characterized by white pustules (blisters of noninfectious pus) surrounded by red skin. The pus consists of white blood cells. It is not an infection, nor is it contagious. Pustular psoriasis can occur on any part of the body, but occurs most often on the hands or feet.
5. Erythrodermic [eh-REETH-ro-der-mik] psoriasis is a particularly severe form of psoriasis that leads to widespread, fiery redness over most of the body. It can cause severe itching and pain, and make the skin come off in sheets. It is rare, occurring in 3 percent of people who have psoriasis during their life time. It generally appears on people who have unstable plaque psoriasis.
Individuals having an Erythrodermic psoriasis flare should see a doctor immediately. This form of psoriasis can be life-threatening. Complications may include Dehydration, Impaired thermoregulation and hypothermia, Overwhelming infection, Protein loss and edema, Anemia (loss of iron, vitamin B12 and folate), Lymphadenopathy and Death due to Cardiac failure.
About 11 percent of those diagnosed with psoriasis also have psoriatic arthritis. Approximately 30 percent of people with psoriasis will eventually develop psoriatic arthritis. It is important to treat psoriatic arthritis early on to help avoid permanent joint damage.
Treating moderate to severe psoriasis and psoriatic arthritis usually involves a combination of treatment strategies. Besides topical treatments, your doctor may prescribe phototherapy (also known as light therapy). Your doctor may also prescribe systemic medications, including biologic drugs, especially if your psoriasis is significantly impacting your quality of life.