Actinic Keratosis: 5 Things to Know About This Common Precancerous Skin Abnormality

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Even if you're not familiar with the term actinic keratosis, you've almost certainly seen one before, especially if you have anyone elderly and balding in the family. That's because an estimated 58 million Americans have developed actinic keratoses, particularly on those parts of the body that have gotten a lot of sun over the years. People with fair complexions are at higher risk.

Actinic keratoses are worth knowing a little about, since they're commonly present, commonly treated, and very occasionally can turn into skin cancer.

Here's what to know:

What they look like: Actinic keratoses usually look like red spots with a rough or scaly center, and they occur on sun-damaged parts of the body such as the scalp, face, and neck. They're often easier to feel than to see.

What the risk is: The risk of an individual actinic keratosis transforming into a squamous cell carcinoma is small: only about 0.1 percent per year. However, experts believe that about 60 percent of squamous cell carcinomas arise from a preexisting actinic keratosis.

Signs of conversion to skin cancer: Conversion to a squamous cell carcinoma should be suspected if the actinic keratosis develops thickness or depth, if it becomes tender, if it develops a sore, or if it seems to be quickly growing. Some actinic keratoses, especially the large ones, can be difficult to distinguish from squamous cell carcinomas of the skin and may require biopsy.

Treatment options: Actinic keratoses can be monitored or removed, depending on the patient's preference. (Some actinic keratoses spontaneously go away, especially in younger people.) Ways to remove actinic keratoses include these:

  • Cryotherapy with liquid nitrogen. This "freezing off" works especially well with thin actinic keratoses, is usually easy on the patient, and has good success rates.
  • Surgical removal. Larger actinic keratoses can be shaved off with a scalpel or sometimes scraped out of the skin. This is usually easily done in a doctor's office and allows the actinic keratosis to be submitted to pathology examination, which can help confirm that there's no squamous cell carcinoma present.
  • Topical pharmacotherapy. Certain drugs, when applied to the skin, can remove actinic keratoses. Although the success rate is usually not as good as cryotherapy or surgical removal, topical therapy can be a reasonable approach for someone with multiple small actinic keratoses. Topical 5-fluorouracil and topical imiquimod are two drugs that can be used for this purpose.

How to prevent actinic keratoses: Almost all actinic keratoses are believed to be caused by UV exposure, so sun protection is the key to prevention. An Australian study found that use of daily sunscreen for two years decreased the number of actinic keratoses by 50 percent.

To learn more about skin cancer, see also Skin Cancer: What to Know About Three Main Types and 6 Signs You Should See a Doctor About Possible Skin Cancer.

Dr. Leslie Kernisan

Leslie Kernisan is a clinical instructor in the University of California, San Francisco, Division of Geriatrics, and maintains a popular blog and podcast at BetterHealthWhileAging. See full bio