What is Psoriasis? What Causes Psoriasis?

Main Category: Eczema / Psoriasis
Article Date: 08 Mar 2009 - 3:00 PST

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Psoriasis is a dry, scaly skin disorder. Doctors believe that it is genetic and is caused by the immune system being mistakenly "triggered", resulting in skin cells being produced too quickly. Normally, skin cells take about 21-28 days to replace themselves. However, in patients with psoriasis they take around 2-6 days. Psoriasis affects approximately 3% of people globally and usually develops in patients between age 11 and age 45. Despite the fact that it is not a contagious disorder, people with the condition can sometimes suffer from social exclusion and discrimination.

What are the symptoms of psoriasis?

Normally there is a constant shedding of dead cells. However, due to the acceleration of the replacement process, both dead and live cells accumulate on the skin surface. Often this causes red, flaky, crusty patches covered with silvery scales, which are shed easily.

Psoriasis can occur on any part of the body although it is most commonly found on the elbows, knees, lower back and the scalp. It can also cause intense itching and burning.

Who is at risk?

Psoriasis affects approximately 3% of people globally. It can start at any age, but most often develops between the ages of 11 and 45, often at puberty.

The condition is not contagious and most people have only small patches of their body affected.

There is a genetic link and it tends to run in families. About 30% of people with one first degree relative with psoriasis develop the condition.

This genetic tendency appears to need to be triggered by infection; certain medicines, including ibuprofen and lithium; psychological factors, including stress; or skin trauma.

There is no way of predicting who will develop psoriasis. 50-60% of people who first experience it do not know of anyone else in their family who has had it.

What is plaque psoriasis?

About 80% of those who have psoriasis have this form. 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, although it can occur on any area of the skin.

What is inverse psoriasis?

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 first shows up as lesions that are very red and usually lack the scale associated with plaque psoriasis. It may appear smooth and shiny.

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

What is erythrodermic psoriasis?

Erythrodermic psoriasis is a particularly inflammatory form of psoriasis that often affects most of the body surface. It generally appears on people who have unstable plaque psoriasis, where lesions are not clearly defined. It is characterized by periodic, widespread, fiery redness of the skin.

The erythema (reddening) and exfoliation (shedding) of the skin are often accompanied by severe itching and pain. Erythrodermic psoriasis "throws off" the body chemistry, causing protein and fluid loss that can lead to severe illness.

Edema (swelling from fluid retention), especially around the ankles, may also develop along with infection.

The body's temperature regulation is often disrupted, producing shivering episodes. Infection, pneumonia and congestive heart failure brought on by erythrodermic psoriasis can be life threatening. People with severe cases of this condition are often hospitalized.

What is guttate psoriasis?

This often starts in childhood or young adulthood and resembles small, red, individual spots on the skin that are not normally as thick or as crusty as lesions of plaque psoriasis.

A variety of conditions have been known to bring on an attack of guttate psoriasis, including upper respiratory infections, streptoccocal infections, tonsillitis, stress, injury to the skin and the administration of certain drugs (including antimalarials, lithium and beta-blockers).

This form of psoriasis may resolve on its own, occasionally leaving a person free of further outbreaks, or it may clear for a time only to reappear later as patches of plaque psoriasis.

What is pustular psoriasis?

Primarily seen in adults, pustular psoriasis is characterized by white pustules (blisters of noninfectious pus) surrounded by red skin. It is not an infection, nor is it contagious.

This relatively unusual form of psoriasis affects fewer than 5% of all people with psoriasis.

It may be localized to certain areas of the body, for example, the hands and feet. Pustular psoriasis also can be generalized, covering most of the body. It tends to go in a cycle: reddening of the skin followed by formation of pustules and scaling.

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