Skip to content


Psoriasis can take many forms and varies in severity, but it is most commonly manifested as inflamed patches of skin covered with silvery scales. Once the disease presents itself — usually early in adulthood — it generally recurs throughout an individual's life. Between 10 to 30 percent of psoriasis sufferers also develop an arthritic condition associated with the skin disease.1

Psoriasis may also be classified as to severity of the disease from mild to moderate to severe, depending on the area of skin exhibiting the lesions. By definition, mild psoriasis affects less than 3 percent of the body surface, moderate psoriasis affects 3-10 percent of the surface, and severe psoriasis describes greater than 10 percent involvement.1 For reference, the palm of the hand represents about 1 percent of the skin surface. Psoriasis is not contagious and many treatment modalities are available.

Psoriasis is generally considered to be an autoimmune skin disorder. Scientists also suspect that heredity, illness, and stress may all play a role. Often there is an identifiable "trigger factor" leading to initial activation of the disease. These factors include strep throat, skin injury, medications such as intramuscular injections or oral steroids, or vaccinations.

Types of Psoriasis

Psoriasis presents itself in many different forms. The disease may change over time, appearing on different areas of the skin, worsening, and improving in a cyclical fashion. Over the course of the disease, one form may change into another form and several forms may be present at the same time in one individual.

One of the most common types of psoriasis is plaque psoriasis (also known as psoriasis vulgaris). It appears as inflamed, raised patches of skin covered with silvery scales made up of dead skin cells. Although plaque psoriasis may appear on any area of the body, the most commonly affected areas include scalp, trunk, knees, and elbows. This form of psoriasis is generally mild to moderate in severity. Typically, plaque psoriasis is bilateral.


Although there is no known cure for psoriasis, many treatment options are available. The basis for treatment is to reduce inflammation and slow the skin cell division that is characteristic of the disease. The type of psoriasis, its severity, and patient characteristics such as age, gender, overall health, lifestyle, and medical history, are all considered when determining a course of treatment. If you suffer from psoriasis, talk to your dermatologist about treatment options.

  1. National Psoriasis Foundation Web site. "About Psoriasis: Statistics." Available at . Accessed November 13, 2007