by Molly Froerer

Created on: January 20, 2010

Most researchers agree psoriasis is an autoimmune disease caused by T cells, a type of white blood cell, attacking the skin. These T cells cause a further immune response, including the entry of too many white bloods cells into the skin and rapidly reproducing skin cells. This extra skin and the extra white blood cells cannot be sloughed off quickly enough to make room for the new skin, and the result is red, scaly patches of skin, often on the knees, elbows, and scalp, although any part of the body may be affected.

Psoriasis is not contagious as it is not caused by a virus or bacteria. However, it can be itchy or painful, cause stiff or swollen joints, dry out the skin, and cause embarrassment and stress. It tends to be worse in cold, dry weather, and improve somewhat in the summer.

The causes of psoriasis are not entirely known. There is clearly a genetic component, however, as many cases tend to be found in the same family. It is estimated that approximately ten percent of the population has some genetic tendency toward psoriasis, although only two to three percent of people actually have the condition. Researchers are still not sure what causes psoriasis to develop.

There are several possible triggers to psoriasis. One cause is stress. Stress impacts the immune system, and as psoriasis is an autoimmune disease, it can cause a flare-up. Additionally, stress often creates sleep pattern difficulties, which can also lead to a decreased immune system.

Another possible trigger to psoriasis is injury. Something as simple as a bug bite, severe sunburn, vaccination, or other even mild trauma to the skin has the potential to start a psoriasis event. The T cells summoned to deal with a real injury may become overzealous and attack the skin unnecessarily.

Repeated infections and other autoimmune diseases can activate psoriasis. Strep throat and thrush are commonly believed to cause the onset of the disease. Furthermore, individuals with HIV or AIDS are more likely to develop psoriasis, likely because their immune system is already compromised.

Unhealthy lifestyle choices can also impact a person’s immune system, rendering it more vulnerable to psoriasis. Smoking, excessive drinking, and obesity all are risk factors as they put strain on the body and its immune system.

Certain medications are also known to cause flare-ups of psoriasis. Lithium, used to treat Bipolar Disorder and other mental illness can do so. Antimalarial drugs can do the same. High blood pressure medication and iodides are also believed to be responsible for triggering psoriasis.

Finally, some people with psoriasis believe weather changes, allergies, and diet can start or worsen psoriasis. Certainly it is true that psoriasis is often worse in the fall and winter and lessens with warmer weather and more sunlight; however, these links have not been clinically proven.

Psoriasis is an uncomfortable and sometimes embarrassing disease. While genetics and the environment are both to blame, experts are not sure what causes the condition to turn on. While psoriasis is not considered a curable disease, there are treatments and relief available.

For more information, go to http://www.psoriasis.org/netcommunity/learn01 or http://www.mayoclinic.com/health/psoriasis/DS00193.

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