Skin problems health centre

Introduction

If you get red, scaly patches on your skin, you may have psoriasis. Some people have only a few patches that get better if they apply a cream. But some people get severe psoriasis that covers more of their body.

You can't catch psoriasis or give it to someone else. There's no cure, but treatment with light and medicine can help clear the patches from your skin.

We've brought together the best research about psoriasis and weighed up the evidence about how to treat it. You can use our information to talk to your doctor and decide which treatments are best for you.

Psoriasis is a skin condition that causes scaly red patches on your skin. There's no cure for psoriasis, but there are treatments that can help.

To understand your psoriasis, it helps to know a little about how your skin works.

Your skin is made up of several layers of cells. The top layer is called the epidermis. All the time, new skin cells form inside the epidermis. Then they slowly move to the outside of your skin. When the cells reach the surface of your skin, they fall off. This turnover of skin cells usually happens over three to four weeks.

If you have psoriasis, this turnover happens much faster. The new skin cells take only three or four days to reach the surface. So the extra cells on your skin’s surface build up and make flaky patches. Sometimes the extra cells cause bad dandruff on your scalp.

We don't fully understand why this happens to some people. The genes you get from your parents may play a part. About one-third of people with psoriasis have a relative with the condition.^[1]

About half of people with psoriasis have markers on a particular chromosome, which seem to be associated with psoriasis, although a specific gene for psoriasis has not yet been identified.^[2]

But just having these genes may not trigger psoriasis. Doctors think that people with psoriasis genes start to get symptoms when their immune system over-reacts to something that happens to the skin. This could be a cut, or a scar from an operation, or a skin infection. Some medicines such as lithium salts (used to treat mania) and beta-blockers (used for heart conditions) may also trigger the condition.

This over-reaction by the immune system seems to cause the inflammation and the quick turnover of skin cells that cause psoriasis symptoms. That’s why treatments for psoriasis include drugs that affect the immune system (often called biological drugs) as well as steroid creams that dampen down inflammation.

Some people with psoriasis find that their symptoms come and go. Some people get flare-ups, when their symptoms get worse. There's some evidence that flare-ups of psoriasis may be linked to:^[1]

• Something stressful happening in your life

• Your habits, such as cigarette smoking

• Being overweight

• Not eating enough fruits and vegetables.

You can get different types of psoriasis.^[3] Here we look only at chronic plaque psoriasis. We don't look at treatments for nail, scalp, or other kinds of psoriasis.

It's important to know that psoriasis is:

• Not infectious. This means you can't catch psoriasis and you can't pass it on to anyone else

• Not caused by poor skin hygiene

• Not a form of skin cancer.