Written by eHealth Navigator

What is psoriasis?

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: plaque, guttate, inverse, pustular and erythrodermic. The most common form, plaque psoriasis, appears as raised, red patches or lesions covered with a silvery white buildup of dead skin cells, called scale. Psoriasis can occur on any part of the body and is associated with other serious health conditions, such as diabetes, heart disease and depression.

According to current studies, as many as 7.5 million Americans have psoriasis. The exact cause of psoriasis is unknown. However, it is understood that the immune system, environmental factors, and family history can play a role.

Psoriasis appears in a variety of forms with distinct characteristics. Typically, an individual has only one type of psoriasis at a time. Generally, one type of psoriasis will clear and another form of psoriasis will appear in response to a trigger.  The National Psoriasis Foundation defines mild psoriasis as affecting less than 3 percent of the body; 3 percent to 10 percent is considered moderate; more than 10 percent is considered severe.  For most individuals, your hand is about the same as 1 percent of the skin surface. However, the severity of psoriasis is also measured by how psoriasis affects a person's quality of life.  Nearly one-quarter of people with psoriasis have cases that are considered moderate to severe.

Plaque psoriasis (psoriasis vulgaris) is the most prevalent form of the disease. About 80 percent of those who have psoriasis have this type. It is characterized by raised, inflamed, red lesions covered by a silvery white scale. It is typically found on the elbows, knees, scalp and lower back.

Guttate [GUH-tate] psoriasis is a form of psoriasis that often starts in childhood or young adulthood. The word guttate is from the Latin word meaning "drop." This form of psoriasis appears as small, red, individual spots on the skin. Guttate lesions usually appear on the trunk and limbs. These spots are not usually as thick as plaque lesions.

Guttate psoriasis often comes on quite suddenly. A variety of conditions can bring on an attack of guttate psoriasis, including upper respiratory infections, streptococcal throat infections (strep throat), tonsillitis, stress, injury to the skin and the administration of certain drugs including antimalarials and beta-blockers.

Inverse psoriasis is found in the armpits, groin, under the breasts, and in other skin folds around the genitals and the buttocks. This type of psoriasis appears as bright-red lesions that are smooth and shiny.

Inverse psoriasis is subject to irritation from rubbing and sweating because of its location in skin folds and tender areas. It can be more troublesome in overweight people and those with deep skin folds.

Primarily seen in adults, pustular psoriasis is characterized by white blisters of noninfectious pus (consisting of white blood cells) surrounded by red skin.

Pustular psoriasis may be localized to certain areas of the body, such as the hands and feet, or covering most of the body. It begins with the reddening of the skin followed by formation of pustules and scaling.

Pustular psoriasis may be triggered by internal medications, irritating topical agents, overexposure to UV light, pregnancy, systemic steroids, infections, stress and sudden withdrawal of systemic medications or potent topical steroids.

Erythrodermic [eh-REETH-ro-der-mik] psoriasis is a particularly inflammatory form of psoriasis that affects most of the body surface. It may occur in association with von Zumbusch pustular psoriasis. It is characterized by periodic, widespread, fiery redness of the skin and the shedding of scales in sheets, rather than smaller flakes. The reddening and shedding of the skin are often accompanied by severe itching and pain, heart rate increase, and fluctuating body temperature.

People experiencing the symptoms of erythrodermic psoriasis flare should go see a doctor immediately. Erythrodermic psoriasis causes protein and fluid loss that can lead to severe illness. The condition may also bring on infection, pneumonia and congestive heart failure. People with severe cases of this condition often require hospitalization.

Known triggers of erythrodermic psoriasis include the abrupt withdrawal of a systemic psoriasis treatment including cortisone; allergic reaction to a drug resulting in the Koebner response; severe sunburns; infection; and medications such as lithium, anti-malarial drugs; and strong coal tar products.

Last Updated on Sunday, 9 December 2012 1:45PM