Causes of Psoriasis

The exact cause of psoriasis isn’t known but it is thought that it is linked to either an overactive immune system, genetics or to environmental factors such as infection.

In people who have the condition, their skin cells are replaced quicker than in someone who has normal skin.

Your skin is made up of layers of cells. The cells are created in the deepest layer of your skin and in someone without psoriasis, over a period of about 28 days, they travel upwards to the surface, where they die and are then shed.

In people who have psoriasis, the skin cells travel to the surface in less than a week, so much faster than normal. As a result, the cells build up and cause flaky, red and crusty patches.

The patch of skin under the affected area is usually red, due to changes in the blood vessels that supply the skin. The vessels can widen and grow in number, causing the redness.

As we mentioned, the exact cause of psoriasis is not known. However, here is a bit more information on the three things that are believed may play a part:

  • Overactive immune system

The immune system creates T-cells and these travel through your body to fight off bacteria and viruses. It is thought that in people who develop psoriasis, these T-cells mistakenly attack healthy skin cells, causing psoriasis.

  • Genetics

The genetic side of psoriasis is not yet fully understood, but a lot of people who have the condition also have a close family member with it, which suggests it could be inherited.

  • Environmental factors

If you have the genes that make you more prone to developing psoriasis, it could be triggered by an environmental factor, such as a virus.


For some people, their psoriasis flares up at certain times, then settles back down.

It is not always clear why these flare ups happen, but in some people, they often occur following a certain trigger. Possible psoriasis triggers include:

  • Stress - if the cause of the stress is treated, the psoriasis symptoms may ease.
  • Streptococcal throat infections - these can cause a flare up of guttate psoriasis (small, salmon coloured spots that appear suddenly)
  • Drinking a lot of alcohol – this may lead to a flare up in some people.
  • Sunlight – In many people, the sun can help to relieve their symptoms, but in others, it can make it worse.
  • Trauma to the skin - such as a cut.
  • Smoking – this may cause psoriasis to develop in certain cases and the toxins in the smoke can lead to a flare up.
  • Certain medication – some may trigger psoriasis or lead to it worsening, including lithium, ibuprofen, naproxen, beta-blockers used to treat congestive heart failure, antimalarial medication, some antibiotics and angiotensin-converting enzyme (ACE) inhibitor medicines used to treat high blood pressure.
  • Cold weather - if it’s cold and dry, your skin may dry out, which could lead to a flare up.
  • Hormonal changes - psoriasis in women is more likely to develop or be at its worst during puberty or the menopause, when hormone levels change.
  • Certain immune disorders, like HIV – this can trigger the development of psoriasis, or lead to a flare up.

There is no direct evidence that certain foods trigger psoriasis, although some people report that they can manage their symptoms better by eating more healthily and by avoiding foods that they know from their own experience make their condition worse.

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