What is psoriasis? Psoriasis is a skin disease that causes red, scaly skin that may feel painful, swollen or hot. If you have psoriasis, you are more likely to get some other conditions, including: Psoriatic arthritis, a condition that causes joint pain and swelling. Cardiovascular problems, which affect the heart and blood circulation system. Obesity. High blood pressure. Diabetes. Some treatments for psoriasis can have serious side effects, so be sure to talk about them with your doctor and keep all your appointments.