Psoriasis

What causes psoriasis?

People with psoriasis produce more skin cells than usual.

Skin cells are usually made and replaced every 3 to 4 weeks, but if you have psoriasis this process only takes about 3 to 7 days. This causes a build-up of skin cells and psoriasis symptoms.

It’s not known exactly why this happens, but it may be to do with a problem in the immune system.

The immune system is your body’s defence against disease and infection. However, for people with psoriasis, it attacks healthy skin cells by mistake. This causes skin cells to be produced quicker than usual.

Psoriasis also runs in families so you may be more likely to get it if a family member has it.

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

Psoriasis triggers

Psoriasis symptoms often start or get worse because of a certain event. This is known as a trigger. Knowing your triggers may help you to avoid a flare-up.

Common psoriasis triggers include:

• an injury to your skin – like a cut, insect bite or sunburn
• drinking a lot of alcohol
• smoking
• stress
• hormonal changes, particularly in women – for example, during the menopause
• certain medicines – like lithium, some antimalarial medicines, anti-inflammatory medicines including ibuprofen, and ACE inhibitors (used to treat high blood pressure)
• other immune disorders, like HIV

Who’s most at risk of psoriasis

Psoriasis is a common skin condition that can start at any age. It affects men and women equally.

The severity of psoriasis varies from person to person. Some people will have mild symptoms, but for others it can have a major impact on their quality of life.

Your GP will look closely at your skin to check whether it's psoriasis. In some cases, a small skin sample (biopsy) may be needed to pin down exactly what's causing your symptoms.

If your symptoms are severe, or if your doctor isn't fully certain what's behind them, you may be referred to a dermatologist, a specialist in skin conditions. And if your doctor suspects your joint pain is linked to psoriasis, you may be referred to a rheumatologist, a specialist in joint conditions, to check for psoriatic arthritis.

Treatment for psoriasis depends on where your symptoms are and how severe they are.

There are many treatments to choose from, and it can take some time to find the one that suits you best. Often, doctors combine more than one type of treatment at once.

Talk to your doctor if you feel your treatment is not working, or if you notice any side effects.

Topical treatments

Topical treatments are usually tried first for mild to moderate psoriasis. These are creams and ointments applied directly onto the affected skin.

For many people, topical treatment is enough to keep the condition under control, though it can take up to 6 weeks before you notice a real improvement.

If you have psoriasis on the scalp, you may be given a shampoo along with an ointment.

Emollients

Emollients are moisturising treatments applied straight onto the skin. If your psoriasis is mild, this is often one of the first things your doctor suggests.

Emollients ease itching and reduce scaling. Skin that is well moisturised also tends to respond better to other topical treatments used alongside them.

Emollients come in many forms. You can buy them over the counter at a pharmacy, or get them on prescription from your doctor.

Steroid creams or ointments

Steroid creams or ointments, also called corticosteroids, are used for mild to moderate psoriasis. They help calm inflammation and reduce itching.

Vitamin D analogues

Vitamin D analogue creams may be used together with steroid creams, or in place of them. They work by slowing down how fast skin cells are produced, and they also help reduce inflammation.

Calcineurin inhibitors

Calcineurin inhibitors, such as tacrolimus and pimecrolimus, come as ointments or creams. They dampen the immune system's activity and help settle inflammation.

Doctors sometimes turn to these for psoriasis in sensitive areas, such as the scalp, genitals, or skin folds, when steroid creams have not helped.

Coal tar

Coal tar is a thick, heavy oil. Exactly how it works is not fully understood, but it can reduce scaling, inflammation, and itching. It may be suggested when other topical treatments have not worked well enough.

Coal tar can stain clothes and bedding and has a strong smell. It can also be used together with phototherapy.

Dithranol

Dithranol stops skin cells from being produced so quickly and tends to cause few side effects. It is usually used only for a short period, under hospital supervision.

It is applied to the skin and left on for 10 to 60 minutes before being washed off, and can also be combined with phototherapy.

Phototherapy

Phototherapy treats psoriasis using natural or artificial light.

Artificial light treatment is given in hospitals or specialist centres, usually under a dermatologist's care. It is not the same as using a sunbed.

UVB phototherapy

Ultraviolet B, or UVB, phototherapy uses a wavelength of light that the human eye cannot see. It slows down skin cell production and works well for some types of psoriasis that have not responded to topical treatment.

Each session takes only a few minutes, but you may need to attend hospital 2 or 3 times a week for 6 to 8 weeks.

Psoralen plus ultraviolet A (PUVA)

With PUVA treatment, you are given a tablet containing psoralens, or the psoralen may be applied directly onto the skin. This makes the skin more sensitive to light.

Your skin is then exposed to a wavelength of light called ultraviolet A, or UVA, which reaches deeper into the skin than UVB.

This treatment may be considered if you have severe psoriasis that has not responded to other treatments.

Systemic treatments

If your psoriasis is severe, or other treatments have not worked, a specialist may prescribe systemic treatment. These treatments act throughout the whole body.

They can carry serious side effects, so it is important to discuss the options and the risks involved with your doctor.

There are two main types of systemic treatment: non-biological and biological.

Non-biological

Non-biological treatments are taken as tablets or capsules. They include:

methotrexate, which slows the production of skin cells and reduces inflammation

ciclosporin, which suppresses the immune system

acitretin, which reduces the production of skin cells

Biological

Biological treatments are given as injections. They ease inflammation by targeting overactive cells in the immune system.

Biological treatments include:

etanercept

adalimumab

infliximab

ustekinumab

Psoriatic arthritis is a type of arthritis that can develop in some people with psoriasis. It affects the joints, which may become swollen, stiff and painful.

Some people with psoriasis feel low self-esteem or anxiety, and this can sometimes lead to depression.

Your GP or dermatologist understands the emotional side of living with psoriasis, so talk to them about any concerns or worries you have.

Living with psoriasis

If you have psoriasis, this advice may help.

Do

• use your treatment as prescribed, even once symptoms improve, to help prevent flare-ups
• speak to your healthcare team if you have questions about your treatment or notice any side effects
• keep up healthy habits like regular activity and a balanced diet
• try to reduce stress where you can
• check whether there is a support group in your area for advice on living with psoriasis

Further support

You can find more support and information on psoriasis from organisations like:

• Changing Faces, an organisation for anyone with a scar, mark or condition on their face or body
• The Psoriasis Association, which offers information, advice and support to people affected by psoriasis and psoriatic arthritis

Do not share personal details such as your name, location or other health conditions.