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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 with 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's just a minor irritation, but for others it can have 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.

Why it happens

People with psoriasis have an increased production of skin cells.

Skin cells are normally made and replaced every three to four weeks, 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 isn't fully understood, it's thought to be related to a problem with the immune system. The immune system is your body's defence against disease and infection, but for people with psoriasis, it attacks healthy skin cells by mistake.

Psoriasis can run in families, although 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 isn't contagious, so it can't be spread from person to person.

Read more about the causes of psoriasis.

How psoriasis is diagnosed

A GP can often diagnose 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 determines the exact type of psoriasis and rules 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 if 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 (a doctor 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.

Treating psoriasis

There's no cure for psoriasis, but a range of treatments can improve symptoms and the appearance of 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 aren't effective, 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 severe cases, where the above treatments are ineffective, systemic treatments may be used. These are oral or injected medicines that work throughout the whole body.

Read more about treating psoriasis.

Living with psoriasis

Although psoriasis is just a minor irritation for some people, it can have a significant impact on quality of life for those more severely affected.

For example, some people with psoriasis have low self-esteem because of the effect the condition has on their appearance. It's also quite common 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 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 typically causes patches of skin that are dry, red and covered in silver scales. Some people find their psoriasis causes itching or soreness.

Psoriasis typically causes patches of skin that are dry, red and covered in silver scales. Some people find their psoriasis causes itching or soreness.

There are several different types of psoriasis. Many people have only one form of psoriasis at a time, although two different types can occur together. One type may change into another type, or become more severe.

Most cases of psoriasis go through cycles, causing problems for a few weeks or months before easing or stopping.

You should see your GP if you think you may have psoriasis.

Common types of psoriasis

Plaque psoriasis (psoriasis vulgaris)

This is the most common form, accounting for about 80% of cases. Its symptoms are dry, red skin lesions, known as plaques, which are covered in silver scales. They normally appear on your elbows, knees, scalp and lower back, but can appear anywhere on your body. The plaques can be itchy, sore or both. In severe cases, the skin around your joints may crack and bleed. 

Scalp psoriasis

This can occur on parts of your scalp or on the whole scalp. It causes red patches of skin covered in thick silvery-white scales. Some people find scalp psoriasis extremely itchy, while others have no discomfort. In extreme cases it can cause hair loss, although this is usually only temporary.

Nail psoriasis

In about half of all people with psoriasis, the condition affects the nails. Psoriasis can cause your nails to develop tiny dents or pits, become discoloured, or grow abnormally. Nails can often become loose and separate from your nail bed. In severe cases, your nails may crumble.

Guttate psoriasis

Guttate psoriasis causes small (less than 1cm or 1/3 inch) drop-shaped sores on your chest, arms, legs and scalp. There's a good chance that guttate psoriasis will disappear completely after a few weeks, but some people go on to develop plaque psoriasis.

This type of psoriasis sometimes occurs after a streptococcal throat infection and is more common among children and teenagers.

Inverse (flexural) psoriasis

This affects folds or creases in your skin, such as the armpits, groin, between the buttocks and under the breasts. It can cause large, smooth red patches in some or all of these areas. Inverse psoriasis is made worse by friction and sweating, so it can be particularly uncomfortable in hot weather.

Pustular psoriasis

Pustular psoriasis is a rarer type of psoriasis that causes pus-filled blisters (pustules) to appear on your skin. Different types of pustular psoriasis affect different parts of the body.

Generalised pustular psoriasis or von Zumbusch psoriasis

This causes pustules on a wide area of skin, which develop very quickly. The pus consists of white blood cells and is not a sign of infection. The pustules may reappear every few days or weeks in cycles. During the start of these cycles, von Zumbusch psoriasis can cause fever, chills, weight loss and fatigue.

Palmoplantar pustular psoriasis

This causes pustules to appear on the palms of your hands and the soles of your feet. The pustules gradually develop into circular brown, scaly spots, which then peel off. Pustules may reappear every few days or weeks.


This causes pustules to appear on your fingers and toes. The pustules then burst, leaving bright red areas that may ooze or become scaly. These may lead to painful nail deformities.

Erythrodermic psoriasis

Erythrodermic psoriasis is a rare form of psoriasis that affects nearly all the skin on the body. This can cause intense itching or burning. Erythrodermic psoriasis can cause your body to lose proteins and fluid, leading to further problems such as infection, dehydration, heart failurehypothermia and malnutrition.

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Psoriasis occurs when skin cells are replaced more quickly than usual. This may caused by a problem with the immune system, perhaps due to genetics or environmental triggers.

Psoriasis occurs when skin cells are replaced more quickly than usual. It's not known exactly why this happens, but research suggests it's caused by a problem with the immune system.

Your body produces new skin cells in the deepest layer of skin. 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 aren't fully mature build up rapidly on the surface of the skin, causing red, flaky, crusty patches covered with silvery scales.

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 invading germs such as bacteria, 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's not known what exactly causes this problem with the immune system, although certain genes and environmental triggers may play a role.


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's likely that different combinations of genes may make people more vulnerable to the condition. However, having these genes doesn't necessarily mean you'll 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 develops after a streptococcal throat infection (although most people who have streptococcal throat infections don't develop psoriasis)
  • other immune disorders, such as HIV, which cause psoriasis to flare up or to appear for the first time

Psoriasis isn't contagious, so it can't be spread from person to person.

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Although psoriasis is just a minor irritation for some people, it can have a significant impact on quality of life for those more severely affected.

Although psoriasis is just a minor irritation for some people, it can have a significant impact on quality of life for those more severely affected.

If you have psoriasis, you may find the following advice helpful.

Self care

Self care is an essential part of your daily life. It involves taking responsibility for your own health and wellbeing with support from those involved in your care. Self care includes staying fit and maintaining good physical and mental health, preventing illness or accidents, and caring more effectively for minor illnesses and long-term conditions.

People with long-term conditions can benefit enormously from self care. They can live longer, have less pain, anxiety, depression and fatigue, a better quality of life, and be more active and independent. Having a care plan will help you manage your treatment so that it fits your lifestyle.

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Keep up your treatment

It's important to use your treatment as prescribed, even if your psoriasis improves. Continuous treatment can help to prevent flare-ups. If you have any questions or concerns about your treatment or any side effects, talk to your GP or healthcare team.

Regular reviews

Because psoriasis is usually a long-term condition, you may be in regular contact with your healthcare team. Discuss your symptoms or concerns with them, as the more the team knows, the more they can help you.

Help with health costs

If you regularly pay for more than three prescriptions a month, you may save money with a prescription prepayment certificate (PPC). To check the cost of a PPC, call 0845 850 0030 or check leaflet HC12 (available in some pharmacies or GP surgeries).

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Healthy eating and exercise

People with psoriasis have a slightly higher risk of developing diabetes and cardiovascular disease than the general population, although it's not known why. Regular exercise and a healthy diet are recommended for everyone, not just people with psoriasis, because they can help to prevent many health problems.

Eating a healthy, balanced diet and exercising regularly can also relieve stress, which may improve your psoriasis.

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Emotional impact of psoriasis

Because of the effect that psoriasis can have on physical appearance, low self-esteem and anxiety are common among people with the condition. This can lead to depression, especially if the psoriasis gets worse.

Your GP or dermatologist will understand the psychological and emotional impact of psoriasis, so talk to them about your concerns or anxieties.

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Psoriatic arthritis

Some people with psoriasis develop psoriatic arthritis. This causes tenderness, pain and swelling in the joints and connective tissue, as well as stiffness. It commonly affects the ends of the fingers and toes. In some people, it affects the lower back, neck and knees. Most people develop psoriatic arthritis after psoriasis, but about 20% develop it before they're diagnosed with psoriasis.

There's no single test for psoriatic arthritis. It's normally diagnosed using a combination of methods, including looking at your medical history, physical examinations, blood tests, X-rays and MRI scans. If you have psoriasis, you'll usually have an annual assessment to look for signs of psoriatic arthritis.

If your doctor thinks you have psoriatic arthritis, you'll usually be referred to a specialist called a rheumatologist, so you can be treated with anti-inflammatory or anti-rheumatic medicines.

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Psoriasis doesn't affect fertility, and women with psoriasis can have a normal pregnancy and a healthy baby. Some women find their psoriasis improves during pregnancy, but for others it gets worse.

Talk to your healthcare team if you're thinking of having a baby. Some treatments for psoriasis can be harmful to a developing baby, so use contraception while taking them. This can apply to both men and women, depending on the medication. Your healthcare team can suggest the best ways to control your psoriasis before you start trying for a family.

Want to know more?

Talk to others

Many people with psoriasis have found that getting involved in support groups helps them. Support groups can increase your self-confidence, reduce feelings of isolation, and give you practical advice about living with the condition.

Want to know more?

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Ray, 69, has been chairman of The Psoriasis Association for the last 33 years. He's lived with psoriasis since he was 14 and continues to treat it with coal-tar medication.

Ray, 69, has been chairman of The Psoriasis Association for the last 33 years. He's lived with psoriasis since he was 14 and continues to treat it with coal-tar medication.

"It was 1955 and I was a 14-year-old schoolboy when my psoriasis appeared quite suddenly. I wasn’t sure what it was and didn’t have any experience of it in my family. The GP just said it might go away.

"Within about three weeks it had begun to spread. It was guttate psoriasis, so I had a pattern of little raindrop-shaped red spots that were slightly raised. This quickly spread to plaque psoriasis, and the patches began to get bigger. By then, it was scaling profusely.

"It was one of those conditions that no one knew much about. Doctors said I would just have to learn to live with it.

"I eventually got referred to a district general hospital, where I was treated with coal-tar baths and ointments. In those days, it was awful stuff. It had a powerful smell and was very staining. My mother helped with the treatment and endured the laundry. I had my own linen and bed wear.

"The psoriasis came and went a little, but was always present. Because of the ointments and shampoos, I would smell like a newly paved road, and when it rained my hair gave off this peculiar odour.

"The psoriasis was on my body and hands, but not on my face, and I could manage my scalp by combing my hair a certain way, but people always thought I had dandruff. The psoriasis improved in sunlight, so my condition was better in the summer, but it would always return.

"So I would go to hospital to have my psoriasis treated with ultraviolet light, which gave me a rather dark winter tan. This was an unusual appearance in those days, as we were an ordinary family and there was no jetting off to beaches or ski resorts. I actually received racial abuse a couple of times from people who thought I was Indian or Maltese.

"When I was 16, I wanted to join the Navy. After a few months of competing, I managed to get through to the final stage, which was a medical examination. But then I was rejected. I was told I had a lifelong disease that was inappropriate for the conditions of service. I completely had to rethink what I was doing.

"In 1960, steroid medications came in. I would apply the steroids and then put on an occlusive polythene suit, which covered my trunk, arms and legs. I would be sweating underneath it and I smelt bad, an experience I wouldn’t wish on my worst enemy, even though it was a great innovation at the time.

"My psoriasis still flares up every now and then. Just over a year ago, it went wildly wrong. My legs were swelling and I was in a really bad way, so the doctors said I might have to go into hospital. I ended up taking ciclosporin, which suppresses your immune response. It restored me back to my normal psoriasis state.

"I now use a mild coal-tar preparation twice a day on the affected areas. It’s OK and doesn’t smell quite as bad as it used to. My wife, who I’ve been married to since 1965, has helped me with this virtually every day of our marriage. I have to get up extra early to allow enough time to apply the treatment and get to 9am meetings, and my wife gets up with me.

"I imagine there are hundreds of thousands of people who have to go through this regimen."

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