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What are the causes and triggers of psoriasis

Your Health / Conditions / Skin Conditions / What are the causes and triggers of psoriasis

Published on Jan 18, 2019
Authored by Pfizer Medical Team​​​​​​​


​​​​​​​What causes psoriasis?

We still don't know the exact cause of psoriasis, but research shows that both genetics and the immune system play important roles in its development. In people who have the genes that make them more likely to develop psoriasis, a trigger – such as an infection, stress, injury or certain medicines – sends their immune system into overdrive, causing inflammation and new skin cells to form too quickly.

Normally, we form new skin cells that mature and shed over about 10–30 days – a process that we don't even notice. In psoriasis, the new skin cells form every few days and your body can't shed the dead skin cells quickly enough, so they build up into psoriasis plaques.

Because the immune system and inflammation are involved, psoriasis is called an immune-mediated inflammatory disease or IMID.

How are genes involved?

Our genes provide the instructions for our cells and spell out what your hair and eye colour will be, how tall you should grow, how strong you can be, and even how some foods taste to you.   Sometimes there is a misstep in how certain genes work and this can increase your risk of developing certain health problems.

Scientists are working hard to understand the genes involved in psoriasis and have found 25 different genes that make a person more likely to develop the skin condition.

Who gets psoriasis?

Psoriasis affects an estimated 2 per cent of people worldwide, and affects women and men equally. It can occur at any stage of life, but often begins in young adults.

About one-third of people with psoriasis have family members with the condition.

What are the common psoriasis triggers?

Even if you have the genes that make you more likely to develop psoriasis, the condition needs a trigger to set it off for the first time and to cause existing psoriasis to flare.

Common psoriasis triggers include:

  • stress – one of the common triggers
  • skin injuries – like cuts, scratches, bumps and bites
  • infections – like strep throat or a virus
  • certain medicines
  • alcohol
  • smoking

Keep reading to learn more about these triggers, what might be triggering your psoriasis, and how you might be able to avoid these to help prevent a flare.


  1. National Psoriasis Foundation (US). About Psoriasis. Accessed 13 November 2018.
  2. The Australasian College of Dermatologists. A to Z of Skin: Psoriasis. Accessed 13 November 2018.
  3. WebMD. Psoriasis. Accessed 14 November 2018.
  4. DermNet NZ. Topics A–Z: Psoriasis. Accessed 14 November 2018.
  5. National Psoriasis Foundation (US). Causes and Triggers. Accessed 14 November 2018.
  6. WebMD. 12 Psoriasis Causes and Risk Factors. Accessed 15 November 2018.

Last reviewed 15/08/2019

External references

Psoriasis Australia
The Australasian College of Dermatologists
Health Navigator New Zealand

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