Actinic keratoses.

Actinic keratoses are premalignant lesions of the epidermis arising on sun-damaged skin. Sun exposure, skin color, tanning ability and heredity are important factors in their development. Actinic keratoses must be distinguished from seborrheic keratoses, squamous cell and basal cell carcinomas and keratoacanthomas. Treatment depends on the location and the extent of disease.