Actinic Keratoses

Actinic Keratoses (AKs) are common skin lesions. Caused by years of sun exposure, AKs also are called solar keratoses or sun spots. Fair-skinned people are more susceptible, and AKs tend to appear on skin that receives the most sun. The forehead, ears, neck, arms, hands, lower lip, a bald scalp, and lower legs of women are common sites. No matter where AKs develop, they are considered the earliest stage in the development of skin cancer.

Like skin cancer, AKs develop when ultraviolet (UV) light from the sun damages cells in the skin. When AKs form, the affected skin cells are the keratinocytes. These tough-walled cells make up 90 percent of the epidermis (the outermost layer of skin) and give the skin its texture. Changes to these cells cause the skin to become rough and scaly. Bumps or small horn-like growths form. If the cells continue to change, AKs can progress to squamous cell carcinoma, a type of skin cancer.


The typical actinic keratosis (AK) is a dry, scaly, rough bump that is skin-colored to reddish-brown. The lesion may range from the size of a pinhead to larger than a quarter. Some skin-colored AKs may be easier to feel than see. When touched, these often feel like sandpaper.

Sometimes an AK grows rapidly upward, causing it to resemble the horn of an animal. When this happens, the AK is called a cutaneous horn. Horns vary in size from that of a pinhead to a pencil eraser. Some horns grow straight; others curve. Cutaneous horns often form on the ears, which tend to receive years of sun exposure. AKs also commonly form on the lower lip. An AK on the lower lip is known as actinic cheilitis and looks like a diffuse, scaly patch on a dry, often cracked, lip.

No matter where an AK forms, it can seem to disappear for weeks or months and then return. This also can happen when an AK is scraped off. The damaged cells continue to grow, and the AK returns.


Upper West Side Dermatology offers the following treatments for actinic keratoses:


The most common treatment for AKs, cryosurgery, involves applying a cryogenic (extremely cold) substance, usually liquid nitrogen, to the lesion. This freezes the surface skin, causing the skin to flake off. New skin forms. The main side effect is skin redness; blistering may occur.


To destroy AKs, patients apply a cancer-fighting cream or lotion (e.g., 5-fluoruracil,) to their skin. Red spots may remain on the treated skin for a while. Another treatment option such as cryosurgery may be necessary to treat thicker lesions that a cream or lotion cannot fully penetrate.


A solution that makes the skin more sensitive to light is applied and left on the skin. After a few hours, the treated skin is exposed to “blue” or “red” light, which activates the solution and destroys the AKs. Areas of redness may develop in treated regions. These will fade after several days.