Psoriasis

Psoriasis is a skin condition that tends to run in families. The most common form causes red, flaky patches of skin covered with raised silvery scales, known as plaques.

These appear on the skin or scalp and can be mild to severe. Psoriasis is not contagious, so it cannot be caught from someone else. There is no cure for psoriasis, however, there are many effective treatment options. It affects men and women in equal numbers and may appear for the first time at any age.

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The Dermatology Quality of Life Index (DLQI) consists of 10 questions assessing the effects of psoriasis on various aspects of quality of life. A score of 0 (not impaired) to 30 (severe impairment) is produced.

Key points

  1. Psoriasis is an inflammatory skin condition that causes red, scaly patches of skin.
  2. Medicated creams and lotions are the most common treatment for psoriasis.
  3. Phototherapy provides a safe and effective second line therapy.
  4. Systemic medications are available for people whose psoriasis does not respond to other treatments.
  5. Approximately 20 - 30% of people with psoriasis develop joint problems known as psoriatic arthritis.

Causes

It is not known what causes psoriasis. It does run in families and it is associated with arthritis. This makes it likely that it has a genetic origin, operating through the immune system of the body.

The skin symptoms typical of psoriasis are due to abnormal cell growth. In normal skin, cells matures in 28 to 30 days. In psoriasis, skin cell are made ten times as fast. This means they don't have enough time to mature. As a result, the immature cells to stick together, creating the thick scales seen in psoriasis.

The following can trigger an onset or aggravate the disorder:

  • skin injury - including severe sunburn
  • infections
  • stress
  • certain medications
  • alcohol
  • smoking
  • hormonal changes.

A sudden severe shock can start psoriasis for the first time and also can cause any existing psoriasis to flare. This can make the person with the psoriasis more aware and concerned about the skin problem.

Psoriasis sufferers commonly experience metabolic syndrome - a disorder of energy utilisation and storage. Components of metabolic disorder include: obesity, high blood lipids (fats), high blood pressure and insulin resistance. Metabolic syndrome increases the risk of developing cardiovascular disease and diabetes.

Symptoms

About 90% of people with psoriasis have a form known as plaque psoriasis. Symptoms include:

  • red, scaly patches (plaques)
  • flaking skin
  • some people may experience itchiness.

Psoriasis is usually located over the elbows and knees. However, any area may be affected, including armpits, groin, palms and soles. It can also result in nail changes, although this is more common in people with psoriatic arthritis.

The severity of psoriasis varies greatly from person to person. For some people, it is quite mild; for others it can result in widespread, itchy, flaky skin and painful, inflamed joints. Even for those with mild disease, living with a chronic, visible skin disease can have a huge impact on their quality of life. As a consequence, people with psoriasis are more likely to:

  • suffer from depression
  • drink too much alcohol
  • smoke
  • be unemployed

Psoriatic arthritis

Approximately 30% of patients with psoriasis will develop psoriatic arthritis. Early morning stiffness is a common sign of this inflammatory joint disease. Other symptoms of psoriatic arthritis includes tenderness, pain, discomfort, throbbing or swelling in one or many joints.
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Diagnosis

Dermatologists are specialists in diagnosing and treating skin conditions, including psoriasis. Your doctor may refer you to a dermatologist if:

  • they are uncertain of the diagnosis of psoriasis
  • topical therapies have failed, or are difficult due to the extent of psoriasis
  • you are having an acute flare
  • your psoriasis is in difficult and challenging sites eg scalp, flexural, genital, hands and feet.

Treatment

If you have psoriasis, you will get a personalised treatment plan that takes into account your overall medical condition, age, lifestyle, severity, duration of the psoriasis and expectations of treatment. Various treatments, combinations of treatments and many visits to the doctor may be necessary before the psoriasis is controlled.

Types of treatment for psoriasis

A wide variety of treatments are available and may be used in combination:

  • Topical therapies. Creams and moisturisers that are placed on the skin. Tend to be used for mild psoriasis. Includes corticosteroids, vitamin D, dithranol and tar preparations.
  • Phototherapies. Light and lamp treatments. Includes ultraviolet B light and psoralen plus UVA light [PUVA]).
  • Systemics. Medicines that are taken by mouth, or occasionally injected, that work throughout the whole body. Used when psoriasis is widespread or doesn't respond to other treatments. Generally very effective, but can have potentially serious side effects. For this reason, they need to be used with caution. Includes non-biological agents such as cyclosporin, methotrexate and acitretin and biological therapies.

How long will psoriasis last?

There is no way of knowing in any particular case whether your psoriasis will persist for a long time or whether it will go away on it's own. Often it does clear up but it is impossible to predict how long it will take or how long the remission will last.

Self care

To help control your psoriasis and prevent flare ups, it's important to look after yourself and your skin. Try the following at home:

  • Warm baths with a bath oil or tar solution can soften the psoriasis and lift the scale. Bland soaps or soap substitutes are useful. Avoid antiseptics and harsh soaps.
  • Emollients keep psoriasis soft with moisturizing creams to prevent it cracking and becoming sore.
  • Waterproof dressings; small, localised patches of psoriasis may improve when covered with waterproof adhesive dressings.
  • Sunshine in small doses may help to clear psoriasis. However, extreme caution must be used to avoid sunburn. This can cause psoriasis flare ups and lead to skin cancer.
  • Rest is very important, especially bed rest. It gives your body a chance to heal and recover.

Learn more

Psoriasis NHS Choices, UK
Psoriasis DermNet
Treatment of psoriasis DermNet
Psoriasis National Psoriasis Foundation, USA

Credits: Dr Denesh Patel, Dermatologist, Auckland Skin & Cancer Foundation and the Psoriasis Association of New Zealand. Reviewed By: Health Navigator