Psoriasis caused by genetics, external triggers

Psoriasis affects up to 7.5 million Americans, making it the most prevalent autoimmune disease in the country, according to the National Psoriasis Foundation.

An autoimmune disease means the immune system is functioning abnormally by attacking the body it is normally meant to protect. In the case of psoriasis, the immune system dysfunction affects skin cell growth, resulting in chronic, visible inflammation. Psoriasis is a non-contagious disease that typically first occurs between the ages of 15 and 35.

Here is a guide to understanding psoriasis:

Overview
The human body is constantly losing and replacing skin cells. Newly produced cells grow at the bottom layer of the skin, and they take around one month to develop and rise to the skin’s surface. The abnormally aggravated immune system causes this skin production to enter overdrive, and skin cells are produced and move to the surface in one to two weeks. This excess skin begins to accumulate, forming the visible scales and inflammation that characterize psoriasis.

Types
There are various types of psoriasis, distinguished by their visible characteristics. While usually only one type will appear at a time, an individual with psoriasis can develop another form if triggered. Plaque psoriasis accounts for most cases of the disease. It is marked by raised, inflamed lesions with silver-white patches called scales, generally found on the elbows, knees, scalp and lower back. Guttate psoriasis occurs as red spots on the skin, appearing on the trunk and limbs, and they are usually thinner than plaque lesions. Inverse psoriasis appears on skin folds around the armpits, groin, breasts, genitals and buttocks. It shows up as bright-red lesions that are smooth and shiny instead of scaly. Pustular psoriasis appears as pus-filled white blisters that are non-infectious.  Erythodermic psoriasis results in severe inflammation that causes the skin to appear widely red. It is particularly dangerous and should be addressed immediately, as a flare-up could result in protein and fluid loss.

Symptoms 
Psoriasis is characterized by skin lesions and inflammation. Additional symptoms can include genital lesions in males, arthritis, nail damage or severe dandruff. The presence of psoriasis also makes an individual more susceptible to other serious disorders. Many people with psoriasis also have psoriatic arthritis, marked by joint pain and swelling. Other chronic conditions that can occur with psoriasis include cardiovascular disease, certain types of cancer and depression. An individual with psoriasis should work continuously with a health care professional to prevent these illnesses from developing.

Cause
Psoriasis is believed to be the result of genetic and non-genetic factors. The National Psoriasis Foundation reports that a child with one parent with psoriasis has a 10 percent chance of inheriting the disease. This number jumps if both parents have the disease, resulting in a 50 percent chance of being diagnosed. Because not everyone with the genes for psoriasis develops it, researchers believe triggers act as catalysts for the disease. Some medications may trigger psoriasis. This is particularly true of lithium, which is primarily used to treat psychiatric disorders. Psoriasis triggers are different for everyone, but common causes include stress or skin injury–an effect known as the Koebner phenomenon.

Treatment
Treatment will depend on the severity of the psoriasis. Different therapies may include topical treatments, light therapy and medication. Topical treatments are applied directly to the skin just like a lotion. These ointments can help slow down cell growth as well as alleviate itchiness or inflammation. Light therapy, also called phototherapy, involves a prescribed and controlled regimen of exposing the skin to ultraviolet rays. When topical treatments and phototherapy are inadequate, health care professionals may prescribe medication to help control skin cell growth.