SPEAKER: Psoriasis starts inside your body when your immune system starts attacking healthy skin cells by mistake. Usually, new skin cells are made every few weeks. But with psoriasis, this gets sped up to just a few days. All these extra cells build up on the surface of your skin faster than your body can shed them. When this happens, you get itchy sore patches called plaques on your knees, elbows, back, scalp, and other places. Plaques are usually thick, raised, and covered with silvery-white scales. Your psoriasis is severe when it covers more than 10% of your body or happens on your face, palms, or soles of your feet. While there's no cure, there are treatments that can help. For severe psoriasis, a combination of different treatments might work best.