Psoriasis

Psoriasis Slideshow Pictures How Much Is Psoriasis Affecting Your Life? Is Your Psoriasis Treatment on Target?

Medical Author:

Harvey Lui, MD, FRCPC

Medical Editor:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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• Psoriasis Overview
• Psoriasis Causes
• Psoriasis Symptoms and Signs
• When to Seek Medical Care
• Psoriasis Diagnosis
• Psoriasis Treatment
• Self-Care at Home
• Medical Treatment
• Psoriasis Medications
• Psoriasis Surgery
• Other Therapy
• Follow-up
• Psoriasis Prevention
• Psoriasis Prognosis
• Support Groups and Counseling
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• Psoriasis Pictures
• Synonyms and Keywords
• Authors and Editors
• Read more on Psoriasis from Healthwise
• Viewer Comments: Psoriasis - Effective Treatments
• Viewer Comments: Psoriasis - Symptoms

Psoriasis Overview

Psoriasis is a common and chronic skin disorder. Plaque psoriasis is the most common type of psoriasis and is characterized by red skin covered with silvery scales and inflammation. Patches of circular to oval-shaped red plaques that itch or burn are typical of plaque psoriasis. The patches are usually found on the arms, legs, trunk, or scalp but may be found on any part of the skin. The most typical areas are the knees and elbows.

Psoriasis is not contagious but can be inherited. Research indicates that the disease may result from a disorder in the immune system (See Causes).

Factors such as smoking, sun exposure, alcoholism, and HIV infection may affect how often the psoriasis occurs and how long the flares up last.

Approximately 1%-2% of people in the United States, or about 5.5 million, have plaque psoriasis. Up to 30% of people with plaque psoriasis also have psoriatic arthritis. Individuals with psoriatic arthritis have inflammation in their joints and may have other arthritis symptoms. Sometimes plaque psoriasis can evolve into more severe disease, such as pustular psoriasis or erythrodermic psoriasis. In pustular psoriasis, the red areas on the skin contain blisters with pus. In erythrodermic psoriasis, a wide area of red and scaling skin is typical, and it may be itchy and painful.

Psoriasis affects children and adults. Men and woman are affected equally. Females develop plaque psoriasis earlier than males. The first peak occurrence of plaque psoriasis is in people aged 16-22 years. The second peak is in people aged 57-60 years.

Psoriasis can affect all races. Studies have shown that more people in western European and Scandinavian populations have psoriasis than those in other population groups.