Actinic keratosis are rough scaly patches on the skin caused by chronic sun exposure. They are more common in fair skin/blue-eyed people and are precancerous. If left untreated, actinic keratosis may progress to squamous cell skin cancer. Therefore, early treatment of actinic keratosis will reduce the risk of developing skin cancer. Treatments for Actinic Keratosis include: Fluorouracil, Imiquimod, Picato, Diclofenac, Liquid nitrogen, and PDT.