Actinic keratoses are lesions in the outer skin layer caused by too much exposure to the ultraviolet rays of sunlight. They are also the beginnings of skin cancer, most often appearing after age 40. In some areas where climate is mild year-round -- like Florida and California -- these lesions appear in much younger people, even teenagers.
People with fair skin, blond or red hair, and blue or green eyes are most at risk of developing these rough, scaly "bumps." A history of burning rather than tanning also increases risk. If not treated, these bumps can develop into a more serious form of skin cancer. Read more about actinic keratosis.