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Psoriasis Facts

By Laura Semko

Psoriasis is estimated to affect 7.5 million people in the U.S. It often appears between the ages of 15 and 25 but can develop at any age. Though not contagious, the condition is hereditary.


The cause of psoriasis is unknown; however, it’s thought to be caused by abnormally fast-growing and shedding skin cells. The skin cells multiply so quickly, causing the skin to shed every three to four days. Doctors think it occurs when the body’s immune system mistakenly attacks healthy skin cells.

Signs and Symptoms

The hallmark sign of psoriasis is red skin, with scaly white patches. Depending on the type, psoriasis may also cause blisters, small pink spots, or white, flaky skin. The elbows, knees, and torso are most commonly affected.

If you have psoriasis, you might go for awhile with no symptoms. Your skin problems may flare up in response to certain triggers. Cold weather, smoking, stress, colds and other illnesses, dry skin, and insect bites or injuries can bring it about.


Psoriasis is often recurrent and occurs in varying severities. There are several types of psoriasis including discoid psoriasis, guttate psoriasis, and pustular psoriasis. Also called plaque psoriasis, discoid psoriasis is the most common type. Guttate psoriasis is a relatively uncommon type that affects mostly children; it usually develops quickly and after an infection, notably strep throat. Pustular psoriasis is a rare form that develops primarily in adults.

Diagnostic Tests

When the condition progresses to the development of silvery scales, a doctor can usually diagnose psoriasis with a medical examination of the nails and skin. Confirmation of diagnosis may be done with a skin biopsy. A doctor takes a small skin specimen to examine under a microscope.


There is no cure for psoriasis, but treatment can help keep symptoms at bay. The goal of treatment is to reduce inflammation and slow down the rapid growth and shedding of skin cells. Treatment may include ointments and creams to moisturize the skin; sunlight or ultraviolet light exposure performed under a physician's supervision; steroids such as cortisone creams; vitamin D cream; creams containing salicylic acid or coal tar; anthralin, which is a drug that treats the thicker, hard-to-treat patches of psoriasis; methotrexate, which is an anticancer drug that interrupts the growth of skin cells; oral or topical retinoids; and immunosuppressive medications.

Medical Reviewer: Cindy Haines, MD Last Annual Review Date: Aug. 1, 2013 Copyright: © 2000-2010 The StayWell Company, 780 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

Reference: Skin, Hair and Nails section on Better Medicine

Did You Know?

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Psoriasis usually starts between ages 15 and 35.