Who gets psoriasis?
About 2 in 100 people develop psoriasis at some stage. It has a tendency to run in families. It can first develop at any age, but it most commonly starts between the ages of 15 and 25.
What causes psoriasis?
Normal skin is made up of layers of skin cells. The top layer of cells are flattened and are gradually shed (they fall off). New cells are constantly being made underneath to replace the shed top layer. It normally takes about 28 days for a bottom cell to reach the top and to be shed.
People with psoriasis have a faster turnover of skin cells. It is not clear why this occurs. More skin cells are made which leads to a build up of cells on the top layer. These form the flaky plaques on the skin, or severe dandruff of the scalp seen in scalp psoriasis.
There is also a slight change of the blood supply of the skin. This tends to cause some inflammation in the skin. This is why the skin underneath a patch of psoriasis is usually red and inflamed.
The cause of the increased cell turnover and skin inflammation of psoriasis is not known. Genetic (hereditary) factors seem to play a part as about half of people with psoriasis have a close relative also affected. It may be that some factor in the environment (perhaps a virus) may trigger the condition to start in someone who is genetically prone to develop it. Another theory is that the immune system may be 'overreacting' in some way to cause the inflammation. Research continues to try to find the exact cause.
Aggravating factors
In most people who have psoriasis, there is no apparent reason why a flare-up develops at any given time. However, in some people, psoriasis is more likely to flare up in certain situations. These include the following:
- Stress. It is difficult to measure stress and to prove the relationship between stress and psoriasis. However, it is thought that stress can contribute to a flare up of psoriasis in some people. There is some evidence to suggest that the treatment of stress in some people with psoriasis may be of benefit.
- Infections. Psoriasis may flare up if you have a feverish illnesses. In particular, a sore throat caused by a certain type of bacterium is a cause of guttate psoriasis.
- Drugs. Some drugs and medicines may possibly trigger or worsen psoriasis in some cases. Drugs that have been suspected of doing this include: beta-blockers (propranolol, atenolol etc), chloroquine, lithium, anti-inflammatory pain killers (ibuprofen, naproxen, diclofenac, etc), ACE inhibitor drugs, and alcohol. In some cases the psoriasis may not flare up until the medication has been taken for weeks or months.
- Smoking. As mentioned, smoking may help to initially trigger psoriasis to develop in some cases. Toxins from cigarette smoke may also aggravate existing psoriasis.
- Trauma. Injury to the skin, including excessive scratching, may trigger a patch of psoriasis to develop. The development of psoriatic plaques at a site of injury is known as the Koebner reaction.
- Sunlight. Most people with psoriasis say that sunlight seems to help ease their psoriasis. Many people find that their psoriasis is less troublesome in the summer months. However, some people notice the opposite with strong sunlight seeming to make their psoriasis worse. A severe sunburn (which is a skin injury) can also lead to a flare up of psoriasis.
- Hormone changes. Psoriasis in women tends to be worst during puberty and during the menopause. These are times when there are some major changes in female hormone levels. Some pregnant women with psoriasis find that their symptoms improve when they are pregnant, but it may flare up in the months just after having a baby. Again, this is thought to be related to changes in hormone levels.
Average rating:
lyn, over 2 years
I developed Psoriasis after a thoat infection five years ago. I'ld aways had perfect skin so it hit me hard. It don't run in my family, i feel angry about it evan after five years. creams from the docs don't help much and its never got much better. summer is my worse time, having to wear trousers and long sleved tops to cover up my skin so people don't stare at me.It makes me so unhappy. The emotional side-effects of Psoriasis and how to cope would be a good article to.
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