Smoking linked to enduring risk of psoriasis

Oct 29 2007

According to new research smokers have a higher risk of developing the skin condition psoriasis.

Psoriasis affects millions of people and there are many different forms of the disease.

It is a disease which affects the skin and joints and causes red scaly patches to appear on the skin.

The scaly patches are areas of inflammation and excessive skin production and skin plaques quickly accumulate at these sites with a silvery-white appearance.

The plaques frequently occur on the skin of the elbows and knees, but can affect any area including the scalp and genitals.

Psoriasis is thought to be related to the body's immune system and is not contagious but is a chronic recurring condition which varies in severity from minor localised patches to complete body coverage; fingernails and toenails are often affected.

Psoriasis can also cause inflammation of the joints, which is known as psoriatic arthritis which affects ten to fifteen percent of people with psoriasis.

While the exact cause of psoriasis is unknown, but it is believed to have a genetic basis and several factors are thought to aggravate the condition including stress, excessive alcohol consumption, and smoking.

Individuals with psoriasis may suffer from depression and loss of self-esteem so quality of life is an important factor in evaluating the severity of the disease.

There are many treatments available but because of its chronic recurrent nature psoriasis is a challenge to treat.

It is common knowledge that cigarette smoke contains hundreds of toxins and chemicals and cigarette smoking has been linked to a plethora of diseases and conditions.

The U.S. researchers suggest that heavy smokers have a greater risk of the skin condition and which remains for years after they have quit.

The study of 79,000 nurses by researchers at the Harvard Medical School in Boston and the University of British Columbia in Vancouver, Canada, found that people with psoriasis who smoked had the more severe disease.

They believe the toxins in cigarette smoke may affect parts of the immune system associated with psoriasis.

Previous research has also implied a link between smoking and psoriasis but it was unclear whether smoking occurred before the onset of the condition.

This latest study provides long-term data as it reported on 887 cases of psoriasis over a 14-year study period.

The researchers found that compared with women who never smoked, the risk of psoriasis was 37% higher among past smokers and 78% higher among current smokers; what is more the heavier the smoking habit, the higher the risk appeared to be and it took as long as two decades after stopping smoking before the risk fell back to that of non-smokers.

The team also found that exposure to passive smoke during pregnancy or childhood was associated with an increased risk of psoriasis.

Study leader, Dr. Hyon Choi says the findings provide a clear incentive for those with psoriasis to stop smoking as well as those at risk of the condition.

Dr. Choi says stopping smoking may decrease the level of smoke induced inflammation in the body by lowering levels of circulating immune cells.

Experts say people with psoriasis should always aim to cease smoking for their general health and to help improve their psoriasis but psoriasis remains an immensely complex condition and there are people with psoriasis who do not and have never smoked.

The research is published in the American Journal of Medicine.