The Facts
Actinic keratosis (AK) is a lesion that forms on sun-damaged skin. The lesions are small scaly patches on parts of the body, such as the face, ears, bald scalp, arms, and hands, that have been chronically exposed to the sun.
AK is a precancerous condition that affects only the top layer of skin (the epidermis). Ultraviolet (UV) from the sun damages the skin and if left untreated, actinic keratosis can turn into a form of skin cancer called squamous cell carcinoma (SCC). When they are found early, AKs are highly treatable.
AK is more common in people with fair skin. Australia has the highest rate of AK in the world.
Causes
Ultraviolet (UV) light from the sun is the major cause of AK. UV light causes changes in the genetic material of the skin's cells. Changes in certain genes can cause cells to grow abnormally and form lesions.
Long-term exposure to the sun increases a person's risk of AK. That's why AK is more common in older people who have accumulated sun damage to their skin. AK can occur in younger people, but it is more common for those over 60 years old. People who work outdoors are also at higher risk.
Another risk factor for AK is skin type. AK most often occurs in people with fair skin and is rare in people with darker skin. People who develop AK tend to have red or blonde hair, and skin that burns easily and does not tan.
