Actinic keratoses on the scalp of a 78 year old male patient. These are precancerous skin growths caused by sun damage. The damage occurs years before the lesions appear. Actinic, or solar, keratoses are mostly found on areas of skin that are exposed to the sun most often, including the backs of hands and the face. It is important to remove the lesions as they can develop into skin cancer. They may be removed by scraping, freezing with liquid nitrogen, drugs, or surgery. New keratoses often appear at or near the site of a previous keratosis, therefore regular check-ups are needed.