Flare-ups can be mild and affect just a small area of the body, but in severe cases it can be more extensive, crack and bleed, causing great distress. Around two per cent of the UK population (1.3 million people) have psoriasis.
The theory is that psoriasis symptoms are caused by cells in the immune system becoming overactive and speeding up the new skin cell replacement process. The skins cells of people suffering from the condition are replaced in a few days instead of the normal rate of 21 to 28 days. What causes this to happen in the first place is unknown, but experts say it's down to a mixture of genes and environmental triggers.
Flare-ups can be triggered by stress, anxiety, hormonal changes, heavy drinking and some medications, including beta-blockers to treat high blood pressure and angina, as well as lithium and malaria medication. In addition to these common triggers, some types of psoriasis can be caused by a streptococcal throat infection.
Chronic plaque psoriasis is the most common type of psoriasis and causes a rash of red, raised patches with silvery white scales. This most commonly affects the elbows, knees, scalp and lower back and can be itchy, but it does not usually scar the skin.
Other types of psoriasis include scalp psoriasis and guttate psoriasis which is common in children and causes bright pink or red spots on the torso, arms and legs and back. Pustular psoriasis causes small white or yellow blisters to form on top of red skin and other types of psoriasis just affect the feet and hands or sensitive areas such as the genitals.
Some 40-50 per cent of people with psoriasis also have nail psoriasis which causes pitting and ridging of the nails, and the nail plate becomes prone to breaking away from the nail bed.
Psoriatic arthritis produces pain, stiffness and swelling in one or more joints and is associated with psoriasis, although sometimes the arthritis symptoms develop before the psoriasis.
Your GP or a dermatologist can tell if you have psoriasis by the appearance and distribution of skin plaques on the rash. Psoriatic arthritis is diagnosed by a rheumatologist via X-rays and scans.
Who gets psoriasis?
Around one person in every 50 can expect to develop psoriasis at some point in their life. It affects men and women equally and can occur at any age but it does peak in two age brackets: from late teens to early 30s and between 50 and 60.
If one parent has psoriasis there is around a 15 per cent chance their child will develop it and smokers (and ex-smokers) have an increased risk of developing the condition.
Controlling psoriasis can sometimes be a trial and error experience of trying different treatments or different combinations of treatments, but it is worth persevering.
First line treatment is usually topical (creams, ointments and gels) and includes coal tar, this has anti-inflammatory effects and is one of the oldest treatments used to treat chronic plaque psoriasis. Emollients are used to soothe and hydrate the skin.
Corticosteroid (steroid) creams and ointments can help to reduce inflammation, as can Vitamin D analogue creams such as calcipotriol, calcitriol and tacalcitol which helps slow skin cell production.
Phototherapy works by using controlled doses of special natural and artificial light to help slow down the production of skin cells. Typically, you will have two to three sessions a week for around six to eight weeks.
If these treatments don’t work, your psoriasis is severe or you have psoriatic arthritis, you may need to see a dermatologist and be prescribed systemic drugs (meaning they work throughout the whole body). These include oral drugs such as the immunosuppressants methotrexate or ciclosporin, or injected biologics including etanercept and adalimumab.
An oral retinoid called acitretin that helps reduce skin cell production is used to treat severe psoriasis that hasn’t responded to other non-biological medication. If psoriasis flare ups are causing you to feel depressed see your GP who may prescribe anti-depressants.