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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

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

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

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 may become more severe.

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

Common types of psoriasis

Plaque psoriasis

This is the most common form, accounting for about 90% 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. Often nails can 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 is 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.

Acropustulosis

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. This can lead to further problems such as infection, dehydration, heart failurehypothermia and malnutrition.

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