Smoking and Psoriasis Smoking greatly increases the risk of psoriasis and makes the disease much worse. Studies have documented that approximately 20% of cases of psoriasis are related to smoking. Compounds in cigarette smoke negatively impact the immune system and the growth of skin cells to promote psoriasis. The more cigarettes a person smokes per day, the greater his or her risk of developing psoriasis. Smoking and Psoriasis Statistics Smoking increases the risk of developing psoriasis and it increases the severity of the disease. Here are the statistics regarding psoriasis and smoking. People who smoke have double the risk of developing psoriasis compared to nonsmokers. Female smokers are more likely to develop psoriasis than male smokers. Smoking increases the risk of a type of psoriasis called palmoplantar pustulosis (psoriasis on the hands and feet). Women who smoke 20 cigarettes per day have 2.5 times the risk of developing psoriasis compared to wom