Psoriasis

Psoriasis is a common, chronic, scaly rash that affects people of all ages (about 2% of the population) and it tends to run in families. Psoriasis is also influenced by many environmental factors. It is not contagious and is not due to an allergy.

The most common ages for psoriasis to first appear are in the late teens and in the 50s. It affects men and women equally, although in children, girls are more commonly affected than boys.

About 5% of those with psoriasis will also develop joint pains (psoriatic arthritis), which may involve one or more joints. This can be very debilitating.

What does Psoriasis look like?

Psoriasis is characterised by red, scaly patches of skin, which usually have very well defined edges. It is often symmetrical, affecting both sides of the body. The scale is typically silvery white. Psoriasis can affect any area of skin and it can sometimes be severe enough to require hospitalisation.

What causes Psoriasis?

Exactly what causes psoriasis is not fully understood but there is a lot of active research into this area. The immune system is involved and appears to be overactive in a way that causes inflammation. Specifically, there is excessive production of TH1 cytokines, particularly TNFα.

These have many effects, including growth of extra blood vessels within the skin (causing the red colour) and increased turnover of the skin cells (causing the scaling and thickening of the skin).

Genetic influences

Like most diseases, psoriasis is influenced by inherited  characteristics. Up to 50% of people with psoriasis will know of another affected family member. Patients with a family history of psoriasis tend to develop psoriasis earlier in life than those without a family history. Other factors that can trigger psoriasis includes stress, infections and injury to the skin.

Many psoriasis studies have noted many affected patients to be overweight or obese. Psoriasis is
associated with a greater risk of ischaemic heart disease (angina and heart attack), stroke and peripheral vascular disease.

Is there a cure?

There is to date no cure for psoriasis but satisfactory control of the disease is possible for most patients. Most forms of psoriasis run a fluctuating course with periods of marked improvement and even complete clearance, only to relapse at a later time. There may be several months or years between relapses. A small group of patients have severe, persistent psoriasis that is very difficult to treat and can be very disabling.

Treatment includes topical creams, oral medications, phototherapy and newer immune-modulating drugs (commonly known as biologics).

Alcohol and smoking — There is an association between increased alcohol intake and smoking and the development of severe psoriasis.