People who have psoriasis are more likely to get type 2 diabetes. That's a condition that makes it hard for your body to make and use the hormone insulin. And the worse your skin problem is, the greater your chances of getting diabetes. More research is needed to explain why this happens, but your immune system may have something to do with it. Psoriasis, which causes raised, red, flaky, and itchy patches on your skin, is an autoimmune disease. That means your immune system attacks part of your own body by mistake. In this case, it's your skin. One theory is that psoriasis could change your immune system enough that over time, it starts going after and killing cells that make insulin.