In personal experience and scientific evidence, these are items I have seen cause/trigger Psoriasis. Yes, genetics do play a role in Psoriasis, but often Psoriasis may never come out if not triggered. Or, if a life altering experience, such as those below happens then Psoriasis could be triggered. Psoriasis is not contagious. If a person has a large outbreak of Psoriasis that does not mean it will happen again.

1. Secondhand smoke (from cigarettes, pipes, tobacco and others)
2. Smoke of other kinds, such as incense
3. Bad air quality / chemicals
4. Stress
5. Skin creams and treatments
6. Genetics
7. Bad foods
8. Weakened state
9. Pesticide exposure
10. Other chemical exposure, such as cleaning agents