Actinic Keratoses (“AKs”) are rough patches located on sun-exposed skin and are a result of chronic sun exposure. They are typically found on the face, ears, bald scalp, forearms, and the backs of hands. Correspondingly, the frequency of actinic keratoses increases with each decade of life, is greater in residents of sunny countries closer to the equator, and is greater in persons with outdoor occupations. Similar lesions may develop due to artificial sources of ultraviolet (UV) radiation like tanning salons. The propensity to develop actinic keratoses is genetically influenced, and people with fair features (blond, blue eyes) are more likely to develop AKs due to their larger susceptibility to sun damage. Incidence of actinic keratoses for those with very dark skin is virtually nonexistant.
AKs are common; they provide the second most common reason people in the United States visit a dermatologist. Approximately 1 in 6 Americans will develop actinic keratoses in their lifetime.
Precancerous: Actinic Keratoses are called “precancerous” because a small fraction of these lesions may transform into a skin cancer; the others may remain or disappear even if untreated. However, left untreated for enough time some will develop into squamous cell cancer and invade local tissues. Even if the percentage that any particular actinic turns cancerous is small, patients commonly have many lesions. Therefore, the likelihood that one of the many lesions turns cancerous becomes significant.
Prevention is attained by long term use of sunscreens and protective clothing, especially for those with very light skin.
Treatment is simple, safe, effective and well tolerated, so treatment of all lesions is highly recommended. The measures taken can be chosen to be cosmetically acceptable to the patient. Treatment options include cryotherapy (liquid nitrogen therapy), surgical procedures, and topical therapies.
While topical therapies have been uncomfortable for some patients, the ability to treat large areas of the skin easily makes this a typical choice. The most common topical therapies prescribed are creams containing either fluorouracil or imiquimod, both available in generic form. Fluorouracil acts by interfering with replication of atypical cells, and is the active ingredient in Efudex and Carac. Imiquimod stimulates the immune system to eradicate atypical cells and is the active ingredient in Aldara and Zyclara. To achieve maximum response, these creams are applied to the entire area where AKs are found, not just the visible lesions.