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Psoriasis

Psoriasis is a skin condition that causes red, flaky, crusty patches of skin covered with silvery scales.

Psoriasis is a skin condition that causes red, flaky, crusty patches of skin covered with silvery scales.

These patches normally appear on your elbows, knees, scalp and lower back but can appear anywhere on your body. Most people are only affected in small patches. In some cases, the patches can be itchy or sore.

Psoriasis affects around 2% of people in the UK. It can start at any age, but most often develops in adults under 35 years old. The condition affects men and women equally.

The severity of psoriasis varies greatly from person to person. For some people, it is just a minor irritation, for others it has a major impact on their quality of life.

Psoriasis is a long-lasting (chronic) disease that usually involves periods when you have no symptoms or mild symptoms, followed by periods when symptoms are more severe.

Read more about the symptoms of psoriasis.

When to seek medical advice

You should see your GP if you think you may have psoriasis. They can often diagnose the condition based on the appearance of your skin.

Further tests are usually only necessary if the diagnosis is uncertain, in which case you may be referred to a specialist in skin conditions called a dermatologist.

Read more about diagnosing psoriasis.

Why it happens

Psoriasis occurs when the process by which the body produces skin cells is accelerated. Skin cells are normally made and replaced every three to four months, but in psoriasis this process only lasts about three to seven days. The resulting build-up of skin cells is what creates the patches associated with psoriasis.

Although the process is not fully understood, it is thought the increased production of skin cells is related to a problem with the immune system. The immune system is your body's defence against disease and infection, but in people with psoriasis it attacks healthy skin cells by mistake.

As psoriasis can run in families, there is also thought to be a genetic element to psoriasis. However, the exact role that genetics plays in causing psoriasis is unclear.

Many people's psoriasis symptoms start or become worse because of a certain event, known as a trigger. Possible triggers of psoriasis include an injury to your skin, throat infections and using certain medicines.

The condition is not contagious so it cannot be spread from person to person.

Read more about the causes of psoriasis.

Treating psoriasis

There is no cure for psoriasis, but a range of treatments can improve symptoms and the appearance of the affected skin patches.

In most cases, the first treatment used will be a topical treatment, such as vitamin D analogues or topical corticosteroids. Topical treatments are creams and ointments applied to the skin.

If these are ineffective or your condition is more severe, a treatment called phototherapy may be used. Phototherapy involves exposing your skin to certain types of ultraviolet light.

In the most severe cases where other treatments are ineffective, systemic treatments may be used. These are oral or injected medicines that work throughout the whole body.

Find out more about treating psoriasis.

Living with psoriasis

Although psoriasis is just a minor irritation for some people, the condition can sometimes have a significant impact on your life.

For example, some people with psoriasis have low-self esteem due to the affect the condition can have on your physical appearance. It is also quite common for someone with psoriasis to develop tenderness, pain and swelling in the joints and connective tissue. This is known as psoriatic arthritis.

Speak to your GP or healthcare team if you have psoriasis and you have any concerns about your physical and mental wellbeing. They can offer advice and further treatment if necessary. There are also a number of support groups for people with psoriasis, such as The Psoriasis Association, where you can speak to other people with the condition.

Read more about living with psoriasis.

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Psoriasis

Psoriasis occurs when skin cells are replaced more quickly than usual. It is not known exactly why this happens.

Psoriasis occurs when skin cells are replaced more quickly than usual. It is not known exactly why this happens.

Your body produces new cells in the deepest layer of your skin level. These skin cells gradually move up through the layers of skin until they reach the outermost level. Then they die and flake off. This whole process normally takes around three to four weeks.

In people with psoriasis, this process only takes about three to seven days. As a result, cells that are not fully mature build up rapidly on the surface of the skin, causing red, flaky, crusty patches covered with silvery scales.

It's thought that the skin cells are replaced quickly in people with psoriasis due to a problem with the immune system.

Problems with the immune system

Your immune system is your body's defence against disease and it helps fight infection. One of the main types of cell used by the immune system is called a T-cell.

T-cells normally travel through the body to detect and fight things like infections, but in people with psoriasis they start to attack healthy skin cells by mistake. This causes the deepest layer of skin to produce new skin cells more quickly than usual, which in turn triggers the immune system to produce more T-cells.

It is not known what exactly causes this problem with the immune system, although certain genes and environmental triggers may play a role.

Genetics

Psoriasis runs in families. One in three people with psoriasis has a close relative with the condition.

However, the exact role that genetics plays in causing psoriasis is unclear. Research studies have shown  many different genes are linked to the development of psoriasis. It is likely that different combinations of genes may make people more vulnerable to the condition. However, having these genes does not necessarily mean you will develop it.

Psoriasis triggers

Many people's psoriasis symptoms start or become worse because of a certain event, known as a trigger. Knowing your triggers may help you to avoid a flare-up. Common triggers include:

  • an injury to your skin such as a cut, scrape, insect bite or sunburn (this is known as the Koebner response)
  • drinking excessive amounts of alcohol
  • smoking
  • stress
  • hormonal changes, particularly in women (for example during puberty and the menopause)
  • certain medicines such as lithium, some antimalarial medicines, anti-inflammatory medicines including ibuprofen, ACE inhibitors (used to treat high blood pressure) and beta blockers (used to treat congestive heart failure)
  • throat infections - in some people, usually children and young adults, a form of psoriasis called guttate psoriasis (which causes smaller pink patches, often without a lot of scaling) develops after a streptococcal throat infection, although most people who have streptococcal throat infections do not develop psoriasis
  • other immune disorders, such as HIV, which cause psoriasis to flare up or to appear for the first time

Psoriasis is not contagious so it cannot be spread from person to person.

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Psoriasis

Usually, your doctor will make a diagnosis of psoriasis based on the appearance of your skin. There is no blood test for psoriasis.

Usually, your doctor will make a diagnosis of psoriasis based on the appearance of your skin.

In rare cases, a small sample of skin, called a biopsy, will be sent to the laboratory for examination under a microscope. This will determine the exact type of psoriasis and will rule out other skin disorders, such as seborrhoeic dermatitis, lichen planus, lichen simplex and pityriasis rosea.

You may be referred to a dermatologist (a specialist in diagnosing and treating skin conditions) if your doctor is uncertain about your diagnosis or your condition is severe.

If your doctor suspects you have psoriatic arthritis, which is sometimes a complication of psoriasis, you may be referred to a rheumatologist. Rheumatologists are doctors who specialises in arthritis. You may have blood tests to rule out other conditions, such as rheumatoid arthritis, and X-rays of the affected joints may be taken.

See living with psoriasis for more information about psoriatic arthritis.

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