Psoriasis is a chronic skin condition that occurs in children and adults. The typical appearance is of red, thickened, scaly patches on the skin (plaques). These plaques can vary in size and distribution from person to person. In some people it may affect small areas of skin while others may have large areas covering their body.

What kinds of psoriasis occur in children?

1.Each of the patterns of psoriasis described in adults can be seen in children. These include:

Flexural psoriasis (red areas between skin folds)
Scalp psoriasis (thick scales found on areas of the scalp)
Nail psoriasis (nail dystrophy related to psoriasis)
Acute guttate psoriasis (small red plaques occurring after an infection)
Chronic plaque psoriasis (red plaques with scaling occurring anywhere on the body)
Erythrodermic psoriasis (severe reddening covering most or all of the body)
Pustular psoriasis (severe pustules that arise acutely)
Photosensitive psoriasis (affecting areas of sun exposure)
Guttate, facial and flexural psoriasis are particularly common in children.

What causes psoriasis?

Psoriasis has a strong genetic component and is due to abnormal processes involved in regulation of the immune system.
Individuals may have flares in psoriasis in response to stress, injury, medications and infections (particularly streptococcal tonsillitis).
Psoriasis is not contagious, therefore, affected children do not need to be isolated from other children.

How is the diagnosis made?

The diagnosis of psoriasis is usually made clinically. This involves a doctor examining the skin and making the diagnosis based on the appearance of the affected areas.
The plaques tend to be distributed symmetrically.
They favour certain sites such as scalp, elbows and knees; or; skin folds such as behind ears, armpits and groin.
They are well circumscribed, red and scaly.
There is often a family history of psoriasis.
Occasionally, a skin biopsy may be necessary to distinguish psoriasis from other skin conditions that may appear similar.

How is the severity of psoriasis assessed?

Assessing severity of psoriasis can assist in deciding upon the most appropriate course of treatment. Severity of psoriasis can be determined in the following ways: 

  • Calculate the body surface area involved
  • Estimate a PASI score (psoriasis area and severity index)
  • Use a questionnaire to assess a person’s quality of life

PASI score

A PASI score is a tool used to measure the severity and extent of psoriasis (Psoriasis Area and Severity Index). It takes a few minutes and experience to calculate it accurately.
Intensity

A representative area of psoriasis is selected for each body region. The intensity of redness, thickness and scaling of the psoriasis is assessed as none (0), mild (1), moderate (2), severe (3) or very severe (4).