Causes of psoriasis
The cause of psoriasis is not clear. One theory among researchers is that certain cells in the immune system (called T cells) are triggered and become overactive.
This T cell activity causes inflammation, and the outer layer of skin cells is shed but is replaced much faster than normal – in about 3 to 5 days instead of the usual 28 to 30 days. Since skin cells grow more quickly than they can be shed, they build up on the outer layer of skin to form the characteristic scales.
Experts believe that the immune system is triggered by certain factors to cause psoriasis symptoms. Find out more about common psoriasis triggers.
Risk factors for psoriasis
Psoriasis affects about one million Canadians. It usually appears between the ages of 15 and 35, although it may occur at any age. Men and women are equally affected and people of all races are affected.
There may be a genetic component to psoriasis, so family history is an important risk factor for psoriasis. If you speak to your doctor about psoriasis, be sure to mention any family members who have also had skin conditions.
It is important to note that psoriasis is not contagious and can't be spread to others.
If you have not been diagnosed but would like to learn more about your risk for developing psoriasis, use our Doctor Discussion Guide to help you ask the right questions.