Actinic keratoses (plural of keratosis) are usually considered precancerous, but have to be treated because, left untreated, they can develop into squamous cell cancers. Often actinic keratoses begin as such small irregularities that they are discovered by touch rather than sight, since they have a bumpy texture. Usually actinic keratoses appear on areas exposed to UV light, such as the face, ears, neck, shoulders, or backs of the hands and forearms. More rarely, they may occur in places exposed to extensive X-rays. Most often they appear as elevated red bumps, but they may also appear as pink, tan, or white nodules.