Actinic Keratosis

This information is useful for adults and older adults
Caused by years of exposure to the sun's ultraviolet rays, actinic keratosis is more common with age.

Unlike most skin conditions caused by the sun, actinic keratosis (AK), which is sometimes called solar keratosis, is usually benign. At least 90 percent of these small, scaly skin spots will not turn into cancer, says dermatologist Sean R. Christensen, MD, PhD, a Yale Medicine dermatologic surgeon, who is also an assistant professor of dermatology at Yale School of Medicine.

“Actinic keratosis is an abnormal growth of cells caused by long-term damage from the sun,” he says. “They are not cancerous, but a small fraction of them will develop into skin cancer. Because we don’t know which ones will become cancer and which will not, dermatologists recommend treatment of these lesions,” Dr. Christensen says.

With highly specialized expertise in diagnosing and treating skin cancer, Yale Medicine is a referral-based tertiary care center. This means that dermatologists from other practices send their most challenging, worrisome cases to us for analysis and treatment. "We have had the experience of dealing with thousands of unusual cases over the years," Dr. Christensen says.