Actinic keratosis: epidemiology and progression to squamous cell carcinoma.

Actinic keratoses are a common problem in the population, and one of the most common conditions treated by dermatologists. Risk factors for the development of actinic keratosis are those associated with increased sun exposure and increased susceptibility to sun exposure such as low latitude, working outdoors, light skin, and history of sunburn. The role of the immune system is clear from the frequency of actinic keratoses in transplant patients. There is strong evidence that actinic keratoses can progress to squamous cell carcinoma, underscoring the need to identify and treat patients at risk.