According to the National Institute of Health, psoriasis affects as many as 7.5 million Americans. However, many people have never heard of the disease or unfamiliar with its symptoms.

So, just what is psoriasis, in laymen’s terms.

Psoriasis in general
Psoriasis is a dry, scaling skin disorder. Most doctors believe that it is genetic and is caused by the mistaken triggering of the the body’s immune system, which causes skin cells to produce too quickly. Skin cells usually take about 21-28 days to replace themselves, but in cases of psoriasis, this process can accelerate to only 2-6 days. 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?
All humans constantly shed dead skin cells. However, due to the acceleration of the skin cell replacement process in psoriasis sufferers, both dead and live cells accumulate on their skin surface. This can cause red, flaky, crusty patches covered with scales, which can cause intense itching and burning. Psoriasis can occur on any part of the body although it is most commonly found on the elbows, knees, lower back and the scalp.

Who is at risk?
Psoriasis affects approximately 3% of people. 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 appears to is a genetic link to psoriasis and it therefore tends to run in families. This genetic tendency is often 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. Well over half of the people who first experience it do not know of anyone else in their family who has had it.

What is plaque psoriasis?
This is the most common form of 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, and in other skin folds around the body. 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.

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.

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, injury to the skin and the administration of certain drugs.
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, and it is NOT is it contagious. This rare 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.

For more information about psoriasis, please visit the National Psoriasis Foundation’s website:www.psoriasis.org.