Psoriasis

Skin Problems Slideshow

• Psoriasis Overview
• Psoriasis Causes
• Psoriasis Symptoms
• When to Seek Medical Care
• Exams and Tests
• Psoriasis Treatment
• Self-Care at Home
• Medical Treatment
• Medications
• Surgery
• Other Therapy
• Next Steps
• Follow-up
• Prevention
• Outlook
• Support Groups and Counseling
• For More Information
• Web Links
• Multimedia
• Synonyms and Keywords
• Authors and Editors
• Pictures of Skin Problems - Slideshow
• Related psoriasis articles:
  Psoriasis - on WebMD
  Psoriasis - on MedicineNet

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.

Plaque psoriasis on the elbow. Image courtesy of Hon Pak, MD.


Plaque psoriasis on the back. Image courtesy of Hon Pak, MD.

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.


Pustular psoriasis. Image courtesy of Hon Pak, MD.

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.