Plaque Psoriasis

The scientific name for plaque psoriasis is 'psoriasis vulgaris'. Vulgaris means common in Latin.

What is plaque psoriasis?

As the name suggests plaque psoriasis is marked by the presence of plaques on the skin. The plaques are oval or circular in shape and usually occur in patches.

What are plaques?

The plaques are thickened areas of silvery white skin, which can crack or form scales. Plaques are caused by rapid skin generation associated with this condition.

Psoriasis, plaques & the skin cycle

Normally the skin cycle, in which skin cells are shed and replaced by new skin cells from underneath takes about 28 days.

With psoriasis, the skin generation cycle is speeded up to only 3 or 4 days. This rapid increase in skin cell production is thought to be caused by immune system dysfunction.

Rapid production of skin cells forces premature skin cells to the surface of the skin where they form thick plaques. Underneath the plaques there is inflammation of the skin area caused by a build up of white blood cells (T-cells) under the skin. The skin plaques take on a silver white appearance and the inflammed skin underneath is red.

The plaques can itch and burn. The burning sensation can be brought on when adjacent skin or clothing rubs against the plaques. Heat including hot water baths can also cause a burning sensation in the plaques.

The areas of skin with red plaques tend to be more sensitive to chemicals including some cosmetics and soaps which can cause a burning sensation. Neutral moisturizers can help reduce the burning and itching.

Plaque Psoriasis Incidence & Statistics

Type & Incidence

Of the 7 types of psoriasis, plaque psoriasis is the most common and accounts for approximately 80% of psoriasis cases. In the United States, approximately 5.5 million people have plaque psoriasis.


Both men and women, children and adults can be affected by plaque psoriasis. Both sexes are equally affected. However, females on average develop plaque psoriasis earlier than males.


Whilst both children and adults can be affected by plaque psoriasis, there are two distinct periods in which the onset of plaque psoriasis peaks. The first peak is within the 16-22 age group and the second in the 57-60 years age group.

Race & Population

Plaque psoriasis can affect all races. However there are differences between populations. There is a higher incidence of psoriasis in people from western Europe & Scandinavian.


There is often a genetic component to plaque psoriasis. Those whose family members have psoriasis have an increased chance of getting this disease. Where psoriasis affects both parents, their children have a 50% risk of developing this chronic condition.

Areas Of Skin Often Affected By Plaque Psoriasis

In plaque psoriasis areas of skin become red inflamed and red silver scales form over the plaques.

Plaque psoriasis can affect any part of the skin. However, certain areas of the skin are more likely to be affected.

  • Abdomen
  • Ankles
  • Elbows
  • Knees
  • Lower Back
  • Scalp

Plaque Psoriasis Triggers

There are a number of factors which can trigger psoriasis.

Although plaque psoriasis is a chronic, long term condition, the red plaques can become part of a cycle of reduction and then flaring up again.

The following triggers can cause the initial onset of the red plaque or cause a flare up.

  • Alcohol
  • Drugs
  • HIV Infection
  • Sunlight
  • Smoking
  • Stress
  • An Injury to the skin