Definition of Actinic keratosis:

Actinic keratosis is a small, rough, raised area found on skin that has been exposed to the sun over a long period of time.

Over many years, some actinic keratoses may develop into a type of skin cancer.

Causes, incidence, and risk factors:

Actinic keratosis is caused by sun exposure, but it takes many years or decades to develop.

Risk factors for actinic keratosis include:

• Having fair skin, blue or green eyes, or blond or red hair
• History of kidney or other solid organ transplant (people who take medicines that suppress the immune system)
• Long-term, daily sun exposure (for example, if you work outdoors)
• Multiple, severe sunburns early in life
• Older age