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What is psoriasis?

Psoriasis is an autoimmune disease that causes raised, red, scaly patches to appear on the skin.

It is most commonly found on the scalp, elbows and knees, but can appear anywhere on the body. Psoriasis is not contagious and there is no cure, but it can usually be controlled with treatment.

Psoriasis is a skin condition that most commonly appears as inflamed, red, scaly patches of skin, covered with a silvery white buildup of dead skin cells.

There are different types of psoriasis with distinct characteristics. Generally, an individual has only one type of psoriasis at a time.

  • Plaque psoriasis – the most common form, usually appearing on the scalp, knees, elbows and lower back. Plaques are often itchy and painful, and they can crack and bleed
  • Pustular psoriasis – a more severe form, characterised by white pustules surrounded by red skin
  • Guttate psoriasis – often starts in childhood or young adulthood after a viral illness, and appears as small, red, separate spots on the skin
  • Inverse psoriasis – appears as very red lesions in the armpits, groin, under the breasts and in other skin folds
  • Erythrodermic psoriasis – a rare and particularly inflammatory form that often affects most of the body surface and causes severe itching and pain. This type of psoriasis requires hospitalisation and can be life-threatening.

Causes of psoriasis

To develop psoriasis, you must carry the genes that cause it and be exposed to specific environmental factors or triggers. Scientists believe that at least 10% of people inherit one or more of the genes that cause a predisposition to psoriasis, however only 2-3% of people develop the disease.

Established triggers for psoriasis include stress or injuries to the skin (such as sunburn or scratches). Certain medications may trigger psoriasis, including lithium, anti-malarials, beta-blockers (taken for high blood pressure) and non-steroidal anti-inflammatories used to treat arthritis.

Symptoms of psoriasis

Psoriasis appears as a rash that doesn't go away with an over-the-counter medication. Depending on the type of psoriasis, symptoms may include:

  • Red scaly patches on scalp, elbows, knees and other parts of the body
  • Itchiness – however, many people do not feel itchy at all
  • Shedding of scales of skin

Up to 30% of people with psoriasis also develop psoriatic arthritis, which causes pain, stiffness and swelling in and around the joints and tendons. The joints most likely to be affected are the last joint in the fingers or toes, the lower back, wrists, knees or ankles.

Treatment of psoriasis

There are a number of different treatments available and it may be necessary to try more than one to find the right regimen to manage your symptoms. Often, a topical medication – cream applied to the skin, usually a corticosteroid – is the first treatment tried.

Phototherapy or light therapy – exposing the skin to ultraviolet light on a regular basis, using either equipment like lasers or sunlight – is an effective treatment for psoriasis if it is done with consistency and under medical supervision.

Biologic drugs targeting specific parts of the immune system or systemic drugs like methotrexate and cyclosporin may be prescribed for moderate to severe cases of psoriasis.

Natural or complementary remedies may be included as an aspect of the treatment regime, although not scientifically proven.

While there is little evidence to link diet with psoriasis, many people report that changes to their diet have a positive effect on the symptoms of the disease.

As stress can be a trigger, mind-body therapies such as yoga and meditation may be helpful.

Further information and sources


This article is of a general nature only. You should always seek medical advice if you think you may have the symptoms of psoriasis.