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What is Psoriasis?

Psoriasis is a common and chronic incurable but treatable skin disorder. Plaque psoriasis is the most common form and appears as elevated plaques of red skin covered with silvery scale that may itch or burn. The involved areas 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, elbows, and lower back.

Plaque psoriasis on the back.
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.

Factors such as smoking, sunburn, alcoholism, and HIV infection may prolong the severity and extent of the condition.

A significant percentage of people with plaque psoriasis also have psoriatic arthritis. Individuals with psoriatic arthritis have inflammation in their joints and may have other arthritic symptoms. Sometimes plaque psoriasis can evolve into more inflammatory disease, such as pustular psoriasis or erythrodermic psoriasis.

  • In pustular psoriasis, the red areas on the skin contain small blisters filled with pus.
  • In erythrodermic psoriasis, extensive areas of red and scaling skin are present.
Pustular psoriasis.
Pustular psoriasis. Image courtesy of Hon Pak, MD.

Psoriasis affects children and adults. Men and woman are affected equally.

  • Females develop plaque psoriasis earlier in life than males.
  • The first peak occurrence of plaque psoriasis is in people 16-22 years of age.
  • The second peak is in people 57-60 years of age.

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.

Medically Reviewed by a Doctor on 11/30/2015
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The eMedicineHealth doctors ask about Psoriasis:

Psoriasis - Home Remedies

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Psoriasis - Effective Treatments

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Psoriasis - Symptoms and Signs

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Psoriasis - Causes

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Women with eczema

10 Psoriasis Triggers and Treatments

  1. Stress
  2. Allergies
  3. Alcohol
  4. Cold or Dry Weather
  5. Tattoos
  6. Medications
  7. Infections
  8. Cuts and Bruises
  9. Smoking
  10. Hormones

Read What Your Physician is Reading on Medscape

Psoriasis »

Psoriasis is a chronic, noncontagious, multisystem, inflammatory disorder.

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