Toronto Psoriasis Centre
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all aspects of your psoriasis

What causes psoriasis?

There is no known single cause of psoriasis. However, scientists believe 3 main factors play a role: genetics, your immune system and the environment. The genetic component just means that it is most likely to occur in members of the same family. Of people who suffer from psoriasis, 30% will have a first degree relative with psoriasis as well.

 The configuration of your immune system plays a key role as recent discoveries have shown that in a person with psoriasis, their skin becomes flooded with a type of white blood cell called T-cells. These cells circulate in blood vessels and are part of the immune system which allows us to fight off “invaders” such as bacteria and viruses.

In a person with psoriasis, these T-cells don’t do their job properly. Instead, incorrect signals are sent to the skin causing inflammation, skin cell division that is too quick and blood vessel proliferation.

Environmental triggers such as trauma to the skin, stress, infections, medications and smoking have been linked to psoriasis as well. People often notice new psoriasis lesions 10 to 14 days after the skin is cut, scratched, rubbed, or severely sunburned (Koebner’s phenomenon).

Psoriasis can also be activated by infections, such as strep throat, and by certain medicines (beta blockers, lithium, prednisone, antimalarials, interferon etc.).

Flare-ups sometimes occur in the winter, as a result of dry skin and lack of sunlight.

Winters in Canada can be particularly harsh for patients with psoriasis; Toronto Dermatology Centre offers phototherapy all year round (covered by OHIP/no-charge), although winter time is certainly the most popular time for this treatment.