Actinic Keratoses (AKs)
Actinic keratoses (AKs), also called solar keratoses, are scaly, crusty growths (lesions) caused by damage from the sun’s ultraviolet (UV) rays. They are often elevated or rough in texture. Most become red, but some will be tan, pink, and/or flesh-toned. If left untreated, up to ten percent of AKs develop into squamous cell carcinoma (SCC) over the course of 10 years.
AKs are caused by years of ultraviolet ray (UV) exposure from the sun or indoor tanning beds. They are considered precancerous, and if left untreated, up to ten percent of AKs develop into squamous cell carcinoma (SCC) over the course of 10 years.
- Fair-skinned people with light-colored hair and eyes have a higher risk for developing AKs.
- Excessive time spent in the sun.
- Use of tanning beds or sun lamps, even if it was many years ago.
- Prolonged residence in an area that gets intense sunlight, such as Florida, the Caribbean, or northern Australia.
- Those with conditions or on medications that make them more sensitive to UV rays.
A single AK may range from the size of a pinhead to larger than a quarter. Most AKs are dry, scaly, and rough textured, but not all AKs look alike. Some are skin colored and may be easier to feel than see. These AKs often feel like sandpaper. Other AKs can appear as red bumps, thick red scaly patches or growths, or crusted growths varying in color from red to brown to yellowish black.
Sometimes an AK grows rapidly upward, and you see a growth that resembles 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.
AKs often seem to disappear for weeks or months and then return. This makes treatment important. Left untreated, the damaged cells can continue to grow and skin cancer may develop.
When AKs develop, they tend to appear on skin that receives the most sun, including the:
- forehead, neck, chest, ears
- scalp, especially a bald scalp
- arms or hands
- lower legs, especially in women
- border of the lip (an AK on the lip and surrounding skin is known as "actinic cheilitis" and looks like a white or grayish scaly patch on a dry, often cracked lip)
AKs are diagnosed on physical exam of the skin but some may require a biopsy (sample) if they do not have a classic appearance.
Your dermatologist can perform a biopsy during an office visit using local anesthesia. It is quick, safe and easy to perform. Your dermatologist will take a sample of all or part of the suspicious skin, and the sampled skin will be sent to a lab where it can be examined under a microscope.
American Academy of Dermatology