Psoriasis is a skin disease that causes itchy scaly patches, most commonly on the knees, elbows, trunk and scalp. Psoriasis is a common, long-term (chronic) disease with no cure. It tends to go through cycles, flaring for a few weeks or months, then subsiding for a while or going into remission. This is the most common type of psoriasis. Patches of skin are red, raised and have silvery-white flakes, called scales. They usually show up on your scalp, elbows, knees, and lower back. Image by: https://www.instagram.com/p/CQ6iuYahjTT/?utm_medium=copy_link Credits : Webmd and Mayoclinic