A rash is a general term for an abnormal skin outbreak. When you have a rash, you know that something is wrong, even if you don't know exactly what it is that you're looking at. Causes vary depending on the rash. Some are contagious, and others are not. Take a look at the info-graphic below to learn about some common rashes. Source
I guess psoriasis Causes are not exact. No one knows the exact cause of psoriasis, but experts believe that it’s a combination of things. Something wrong with the immune system causes inflammation, triggering new skin cells to form too quickly. Normally, skin cells are replaced every 28 to 30 days. With psoriasis, new cells grow every 3 to 4 days. The buildup of old cells being replaced by new ones creates those silver scales. Some things that can trigger outbreaks are: Cuts, scrapes, or surgery Emotional stress Strep infections
