Is psoriasis contagious, and what factors contribute to its development without the risk of spreading it to others?

No. Psoriasis is not contagious. Psoriasis is an autoimmune disease. With this condition, there are certain parts of the skin that is replacing itself too fast. It may replace itself in only three days when it should be replacing itself in around 28 days. This can result in red scaly plaques on the skin.