Actinic keratosis is a precancerous skin growth. It appears as a dry, scaly, or crusty spot on the surface of the skin. An actinic keratosis can be as small as pinhead to a spot that is more than 1 inch wide. The spots vary in color from tan, pink, red, or skin-colored. Some are flat, others are raised. An actinic keratosis is more likely to appear on skin that is exposed to the sun, such as the face, ears, back of the neck, a bald head, hands, and arms. About 10% to 15% of actinic keratosis develop into squamous cell skin cancers. Follow the links below to find WebMD's comprehensive coverage about how actinic keratosis is contracted, what it looks like, how to treat it, and much more.