What Is Actinic Keratosis, Exactly?

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Many common skin conditions out there—think skin tags, cherry angiomas, keratosis pilaris—are unsightly and annoying to deal with, but, at the end, of the day, don't pose much of health risk. That's one major thing that makes actinic keratosis different.

This commonplace issue has the potential to become a very serious problem, namely, skin cancer. But that doesn't mean you should freak out if you have one of these rough patches of skin.

While it affects more than 58 million Americans, only 10 percent of actinic keratoses will eventually become cancerous, according to The Skin Cancer Foundation. So, take a deep breath. Ahead, dermatologists explain everything you need to know about actinic keratosis, from causes to treatment.

What is actinic keratosis?

Actinic keratosis, aka solar keratosis, is a type of pre-cancerous growth that appears as small, rough patches of discolored skin, says Kautilya Shaurya, M.D., a dermatologist at Schweiger Dermatology Group in New York City. These patches—most of which are less than one centimeter in diameter, though can grow over time—can be light tan or darker brown. More often, however, they're pink or red, according to Chicago-based dermatologist Emily Arch, M.D., who also points out that the change in skin texture is a defining characteristic. "Often times you can feel these lesions more easily than you can see them. They feel rough to the touch, like sandpaper, and can become scaly," she says. (Related: Reasons Why You Might Have Rough and Bumpy Skin)

Although similar in both name (keratosis) and appearance (rough, brown-ish), actinic keratosis, or AK, is not the same as seborrheic keratosis, which is a common skin growth that is a bit more raised and has a more of a waxy texture, according to the American Academy of Dermatology.

What causes actinic keratosis?

The sun. (Remember: it's also called solar keratosis.)

"Cumulative exposure to UV rays, both UVA and UVB, causes actinic keratosis," says Dr. Arch. "The longer an individual is exposed to UV light and the more intense that exposure is, the higher the risk of developing actinic keratoses." This is why it's often seen in older patients with fair skin, especially those who live in sunnier climates or with outdoor occupations or hobbies, she points out. Similarly, they often appear on areas of the body that are chronically exposed to the sun, like the face, tops of the ears, scalp, and backs of the hands or forearms, says Dr. Arch.

UV radiation leads to direct damage to the skin cells' DNA, and over time, your body isn't able to repair the DNA effectively, explains Dr. Shaurya. And that's when you start to end up with abnormal changes in skin texture and color.

Is actinic keratosis dangerous?

In and of itself, actinic keratosis usually doesn't pose an immediate health risk. But it can become problematic in the future. "Actinic keratosis can be dangerous if left untreated because it's a pre-cursor to skin cancer," cautions Dr. Shaurya. To that point...

Can actinic keratosis turn into cancer?

Yes, and more specifically, actinic keratosis can turn into squamous cell carcinoma, which occurs in up to 10 percent of actinic keratosis lesions, says Dr. Arch. Not to mention that the risk for AK to become cancerous also increases the more actinic keratoses you have. In areas of chronic sun damage, such as the backs of the hands, face, and chest, there are usually a greater number of actinic keratosis patches, which increases the risk of any one of them turning into skin cancer, she explains. Plus, "having actinic keratoses implies significant UV light exposure, which increases your risk for other skin cancers as well," notes Dr. Arch.

What's does actinic keratosis treatment entail?

First and foremost, make sure to play the prevention game and use a broad-spectrum sunscreen with at least an SPF 30 day-in and day-out, according to the American Academy of Dermatology (AAD). This simple skin-care step is the easiest and best way to ward off not only actinic keratoses and all kinds of other skin changes (think: sunspots, wrinkles), but also significantly reduce your risk of developing skin cancer. (Wait, do you still need to wear sunscreen if you're spending all day indoors?)

But if you do think you have actinic keratosis, see your derm, stat. Not only will he or she be able to check it and make sure it's diagnosed correctly, but they'll also be able to recommend an effective treatment, says Dr. Shaurya. (And no, there is definitely no DIY, at-home actinic keratosis treatment, so don't even think about it—or Google it.)

The number of lesions, their location on the body, as well as the patient's preference all play a role in determining which treatment is best, says Dr. Arch. A single rough patch of skin is usually frozen off with liquid nitrogen (which, btw, is also used to get rid of warts). The process is quick, effective, and painless. But if you have many lesions clustered together in one area, experts typically recommend treatments that can address the entire area and cover a larger amount of skin, she explains. These include prescription creams, chemical peels—usually a medium-depth peel that's also used cosmetically to help improve lines and wrinkles—or one to two sessions of photodynamic therapy—which involves using blue or red light to kill the cells in the actinic keratoses. Generally speaking, these are all quick and easy treatments with little to no downtime and should remove the actinic keratosis completely so that you no longer see it.

Granted, because they are caused by sun exposure, it's essential to be diligent with your daily SPF application; that is by far the best preventative measure you can take, says Dr. Arch. Otherwise, actinic keratosis can reoccur, and once again have the potential to turn into skin cancer—even in an area that was previously treated.

If for some reason the treatment doesn't completely remove the actinic keratosis or the lesion is larger, more raised, or looks different than a traditional actinic keratosis, your doc may also biopsy it to ensure it hasn't already turned into skin cancer. In the event it has already turned cancerous, your dermatologist will then discuss the best treatment options (which differ from the above) for you, based on your individual diagnosis.

At the end of the day, "if actinic keratoses are treated early, skin cancer can be prevented," says Dr. Shaurya. So if you have an actinic keratosis patch, or even think you may have some, get yourself to the derm, ASAP. (Not to mention, you should be visiting your derm for a regular skin check anyway.)