Psoriasis is a common condition where the skin gets red and scaly; psoriasis can cause itching, discomfort, and sometimes pain. It affects 2% to 4% of the world’s population. While it can begin at any age, psoriasis has 2 peaks of onset, the first at age 20 to 30 years and the second at age 50 to 60 years. It affects men and women equally. One-third of patients with psoriasis develop psoriatic arthritis, a progressive joint disease that can limit movement if untreated. Patients with severe psoriasis are also at higher risk than the general population for high blood pressure, diabetes, heart attacks, strokes, obesity, and depression.