Patient information from BMJ

Psoriasis: what is it?

Last published:Aug 06, 2021

If you get red patches on your skin covered with silvery scales you may have psoriasis. There is no cure for psoriasis but there are treatments that can help control it.

What happens?

Your skin is made up of several layers of cells. New cells are constantly being made to replace the older ones as they die and flake away. The new cells move from the inside to the outside of your skin. When these cells reach the surface of your skin, they fall off.

This turnover of skin cells usually takes three to four weeks. But if you have psoriasis new skin cells take only three or four days to reach the surface. These extra cells build up and make flaky patches (called plaques) on the surface of the skin. Sometimes the extra cells can cause severe dandruff on the scalp.

Doctors aren’t sure why psoriasis happens to some people. The genes you get from your parents may play a part. It's also possible that stress can cause psoriasis to flare up at times.

You can get different types of psoriasis. This information covers chronic plaque psoriasis. We don't look at treatments for nail or scalp psoriasis, or for other kinds.

Psoriasis is not contagious. So you can’t give it to, or catch it from, anyone else.

What are the symptoms?

Psoriasis patches or 'plaques' are red and covered with silvery scales. They have clear edges separating them from the surrounding skin. They can be different shapes and sizes. The patches may be itchy. Sometimes the plaques split and bleed.

Your skin plaques will probably come and go. They may last for a few months at a time, or they may never really go away. Some people have only two or three patches at a time, while others have a lot of plaques all over their body.

You may also get some of these symptoms if you have chronic plaque psoriasis:

• Changes to your nails. Your nails may look pitted, or separate from the nail bed. This happens to about a third of people with psoriasis

• Painful, stiff joints (arthritis). This happens to up to 10 in 100 people with psoriasis. It usually affects the joints at the ends of your fingers and toes.

What will happen to me?

Psoriasis is what doctors call a 'chronic' condition. This means that it can last for a long time, and that it can affect people to some degree for the whole of their lives. But that doesn't mean it affects everyone all the time: most people with psoriasis find that it comes and goes.

Psoriasis can be unpleasant and troublesome, but it is not likely to affect your general health. Most people can control their symptoms with treatment.

For many people with psoriasis the main problem is feeling self-conscious about how their skin looks. Some people don't want to do things where people can see a lot of their skin, such as swimming. Some people don't want to go out socially.

It might help to know that hundreds of thousands of people have this condition, and that many of them have the same feelings about it. Although there is no cure for psoriasis this condition can be controlled. And you can live life the way you want to.

Where to get more help

Coping with psoriasis from day to day can get you down. It might help to talk to other people who have the condition. There are charities and support groups in many countries that can offer many kinds of support. For example, in the UK, the Psoriasis Association (www.psoriasis-association.org.uk) can put you in touch with local groups, and offer advice and help.