Question: what are white crusty spots on skin?
Answer: Actinic keratosis. Actinic keratoses are scaly spots or patches on the top layer of skin. With time the spots or patches may become hard with a wartlike surface. An actinic keratosis (ak-TIN-ik ker-uh-TOE-sis) is a rough, scaly patch on your skin that develops from years of exposure to the sun.