Sometimes red scaly patches can be a sign of skin cancer however they can also be a sign of precancerous lesions called actinic keratosis.  Actinic keratoses are red scaly spots usually found on the face, arms, and hands.  They are caused by sun damage over time.  Most patients have multiple spots at one time.  These spots are important to treat because they have the ability to turn into squamous cell carcinoma if left untreated over time.  Treatment options range from liquid nitrogen to topical chemotherapy creams, or a light treatment called photodynamic therapy.