What are Actinic Keratoses?

Actinic keratoses (AKs) are dry, scaly, rough-textured patches or lesions that form on the outermost layer of the skin after years of exposure to ultraviolet (UV) light, such as sunlight. These lesions typically range in color from skin-toned to reddish brown and in size from that of a pinhead to larger than a quarter. Occasionally, a lesion grows to resemble an animal horn and is called a “cutaneous horn.”

It is important that anyone with AKs be under a dermatologist’s care. AKs are considered the earliest stage in the development of skin cancer and have the potential to progress to squamous cell carcinoma, a type of skin cancer that can be fatal. Anyone who develops AKs has extensive sun-damaged skin. This makes one more susceptible to other forms of skin cancer, including melanoma. Melanoma is considered the most lethal form of skin cancer because it can rapidly spread to the lymph system and internal organs.

Why the Term “Actinic Keratoses”
The two words “actinic” and “keratoses” precisely describe what has happened to the skin. “Actinic” (ak-‘ti-nik) comes from the Greek word for ray, “aktis,” and indicates that radiant energy has produced chemical changes. The word “keratoses” (ker-ah-TOE-sees) means the skin has become hard and callous. Therefore, AKs are areas of calloused skin caused by chemical changes brought about by exposure to radiant energy, such as sunlight. The lesions may also be called “solar keratoses.”

When such a lesion occurs on the lip, dermatologists call the condition “actinic cheilitis” (key-LITE-iss).   “Cheilitis” means inflammation of the lips. Actinic cheilitis is characterized by a diffuse scaling on the lower lip that cracks and dries. Sometimes the lip has a whitish discoloration on the thickened lip.

Causes
Years of sun exposure cause AKs to develop. All AKs, including actinic cheilitis, develop in the skin cells called the “keratinocytes,” which are the tough-walled cells that make up 90% of the epidermis, the outermost layer of skin, and give the skin its texture. Years of sun exposure cause these cells to change in size, shape, and the way they are organized. Cellular damage can even extend to the dermis, the layer of skin beneath the epidermis.

Who Gets Actinic Keratoses?
Individuals with fair skin, a history of cumulative sun exposure, or a weak immune system are at greatest risk for developing AKs. These lesions develop on areas of the body that have received years of sun exposure, such as the face, ears, lip, scalp, neck, forearms, and back of the hands. AKs usually appear after age 40 because they take years to develop. However, even teens can have AKs when they live in areas that receive high-intensity sunlight year round, such as Florida and Southern California.

Research shows that p53, a mutant protein found in sun-damaged cells in the body, is present in more than 90% of people who have AKs and squamous cell carcinomas.

More Americans Developing AKs
Millions of Americans have AKs, and the number continues to grow. In fact, AKs are so common today that treatment for these lesions ranks as one of the most frequent reasons people consult a dermatologist.

A survey conducted by the American Academy of Dermatology (AAD) confirmed what dermatologists have long suspected: The public’s behavior regarding sun protection has not improved significantly over the last two decades. Findings indicate that people are spending more time outdoors, not adequately protecting themselves from the sun, and still believe the appearance of a tan is healthy. The survey also found that younger people tend not to use sunscreen on a regular basis and are more likely to visit a tanning salon today than in the past.

Prevention and Early Detection Key
To prevent AKs and skin cancer, the AAD recommends adopting a comprehensive sun protection program that includes:

  • Avoid deliberate tanning. Ultraviolet light from the sun and tanning beds causes skin cancer and wrinkling. If you want to look like you’ve been in the sun, consider using a sunless self-tanning product. When using a self-tanning product, you should continue to use sunscreen.

  • Get vitamin D safely through a healthy diet that includes vitamin supplements. Don’t seek the sun.

  • Generously apply sunscreen to all exposed skin. Before going outdoors, generously apply a sunscreen that has a Sun Protection Factor (SPF) of at least 30 and is broad-spectrum — protects against both ultraviolet (UVA) and ultraviolet B (UVB) rays. While outdoors, re-apply the sunscreen approximately every two hours, even on cloudy days, and after swimming or perspiring.

  • Cover up when you must be in the sun. Wear long sleeves, pants, a wide-brimmed hat, and sunglasses that protect against both UVA and UVB rays.

  • Use extra caution near water, snow, and sand. These reflect the damaging rays of the sun, which can increase your chance of sunburn.

When caught in the early stages, AKs and all types of skin cancer are treatable and in most cases, curable. The key to early detection is frequent skin examinations. Performing regular self-examinations and being screened by a dermatologist as needed can help detect AKs and skin cancer in the earliest and most treatable stages.

If you find a suspicious skin lesion, be sure to see a dermatologist for diagnosis — even if the lesion seems to appear and then disappear for weeks or months and reappear. Dermatologists receive extensive medical training in skin conditions and have the experience necessary to diagnose various skin lesions. An accurate diagnosis is the first step to successful treatment.

Self-treating by picking off the lesions is not effective treatment; the lesions grow back. Since AKs have the potential to progress to squamous cell carcinoma, a sometimes fatal type of skin cancer, AKs should be treated.

What Actinic Keratoses are Not
While the terminology that dermatologists use can seem confusing, the precise terms allow dermatologists to clearly differentiate skin conditions and prescribe appropriate treatment. Described below are some skin conditions that patients may confuse with AKs.  The following conditions are not AKs:

Actinic porokeratosis: Similar in appearance to AKs, this is an uncommon, usually inherited, skin condition characterized by sun sensitivity that causes reddish brown scaly spots to develop, primarily on the arms and legs. The lesions appear after years of sun damage to the skin, so they are typically seen in middle-aged and older individuals. The lesions tend to grow or itch after sun exposure and are fairly resistant to treatment.

Seborrheic dermatitis: This is a red, scaly rash that itches. Seborrhea is excessive oiliness of the skin, especially on the scalp and face, without redness or scaling. If seborrhea progresses to seborrheic dermatitis, redness and scaling appear.

Seborrheic keratoses: Also called “benign keratoses,” these non-cancerous growths have a waxy, pasted-on look and develop on the outer layer of skin. Lesions range in size from a fraction of an inch in diameter to larger than a half dollar. AKs are flatter, redder, and rougher to the touch than seborrheic keratoses.


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Left untreated, AKs may progress to squamous cell carcinoma, a type of skin cancer that can be fatal.

American Academy of Dermatology


Diagnosed AKs









Actinic keratoses on the face


When on the lips, the lesion is
called "actinic cheilitis"

(Photos used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides)


What AKs are Not


A case of disseminated superficial actinic porokeratosis


Seborrheic dermatitis on the face and scalp of an adult patient


Seborrheic keratosis on the chest of an elderly man

(Photos used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides)


 
 
 
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Page last updated 10/19/05

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