Actinic Keratoses (AKs)

What are actinic keratoses?

AKs are considered the earliest stage in the development of skin cancer.  They are common lesions of the epidermis (outer most layer of the skin), and are caused by long-term exposure to sunlight.  AKs are most likely to appear after age 40, however in geographic areas with year-round high intensity sunlight such as Florida and Southern California, AKs may be found in persons as young as teens and twenties.  Half of all older, fair-skinned persons who live in hot, sunny areas have AKs.  The most significant predisposing factor to AKs is fair skin and long-term exposure.

Chronic sun exposure causes skin cells to change size, shape, and the way they are organized.  The skin cells affected in AKs are the keratinocytes.  Keratinocytes are the tough-walled cells that make up 90 percent of the epidermis and give the skin its texture.  Changes in keratinocytes can be seen when the skin becomes rough, scaly, or mottled, and develops bumps or small horn-like growths.  Further changes in cell growth can turn AKs into squamous cell carcinoma, a type of skin cancer.

What do AKs look like?

Actinic Keratoses are found on chronically sun-exposed skin, most commonly on a fair-skinned person, middle-aged or older.  They are commonly found on the sides of the forehead, the ears, the scalp of bald men, and the backs of the hands.  The typical AK lesion is a dry, scaly, and rough skin-colored to reddish-brown “bump” on the skin.  AK lesions may range from the size of a pinhead to larger than a quarter.  Skin-colored AK lesions may be noticed more by tough because they tend to have a sharp, hard scale and feel like sandpaper.  They are often sensitive or “touchy”.  Wrinkling, furrowing, and other signs of sun damage may be present with AK lesions.

Sometimes the skin cells making up an AK lesion undergo abnormal growth and becomes a “cutaneous horn”.  The size of a horn may vary from a pinhead to a pencil eraser; and its shape may be straight or curved.  The external ear is a common site for a cutaneous horn. 

An actinic keratosis can also appear as a scaling lesion on the lower lip that dries and cracks open.  An AK at any location may at times seem to disappear for weeks or months and then return at the same place.  If they are picked off they grow back.

What will the dermatologist do if they think I have an AK?

The basic types of treatment for actinic keratoses are cryosurgery, surgical removal and biopsy, topical chemotherapy, and photodynamic therapy.  Other surgical options that have been used include chemical peels and laser skin resurfacing.

Prevention

Prevention of AKs should begin early in life.  Sun damage to unprotected skin begins early in childhood and puts the child at risk for actinic keratoses and skin cancer later in life.  However, it is never too late to initiate prevention of new actinic keratosis lesions in adulthood.

1. Apply sunscreen with a sun protection factor of 15 or greater while outdoors. 
2. Apply at least 20 minutes prior to sun exposure for maximum sun protection. Wear a broad-brimmed hat and sun protective clothing.
3. Avoid the sun between 10:00 a.m. and 4:00 p.m.
4. Apply sunscreen every 1 ½ hours if you are active outdoors.  Select a broad-spectrum sunscreen that provides both UVA and UVB protection