Actinic Keratosis: A Common Skin Condition That’s Worth Treating

After a summer spent outdoors, you may notice changes in your skin. It’s normal to see new freckles or peeling after a sunburn. These short-term changes fade—but a rough, scaly spot on your face, scalp, ears, or the back of your hands that doesn’t go away after about a month may be actinic keratosis (AK). Sometimes called solar keratosis, AK is one of the most common skin conditions dermatologists treat. It’s caused by years of sun exposure.

Sean Christensen, MD, PhD, and Kathleen Suozzi, MD, both Yale Medicine dermatologic surgeons and associate professors of dermatology at Yale School of Medicine, provide insight into who might develop AKs, how dermatologists identify them, and how they are treated.

An AK is a rough patch of skin composed of cells damaged by years of sun exposure. AKs are one of the most common conditions treated by dermatologists.

The good news: AKs are usually benign, and at least 90% never turn into cancer. “Because we don’t know which ones will become cancer and which will not, dermatologists recommend treatment of these lesions,” explains Dr. Christensen.

No, but it’s often called precancerous. “We use the term precancerous to help patients understand why we care about AKs,” says Dr. Christensen. “AK is not skin cancer, but it has some features under the microscope where the cells look a bit like a type of skin cancer called squamous cell skin cancer.”

Most AKs never become cancer. About 1% of AKs progress to skin cancer each year. Over many years, that risk adds up, so the number of AKs you have matters.

AKs are usually small, less than one-quarter inch. They’re often pink and may be rough or scaly. They may itch or feel tender.

“You can feel it better than you can see it,” says Dr. Christensen. “If you run your finger over it, you can feel a rough spot, kind of like sandpaper.”

AKs tend to appear where your skin has had the most sun over the years, including the face, ears, back of the hands, forearms, and bald scalp.

AKs are increasingly common with age, particularly in people who are 50 and older, because sun damage builds up over time. Dr. Suozzi says AKs are most common in people with fair skin, light eyes, and light hair who have had significant sun exposure or sunburns. They’re also common in people who have spent a substantial amount of time outdoors, for recreation or work.

However, anyone can develop them. People with olive or darker skin can still get AKs and skin cancer. Skin cancer is becoming more common in younger people, and AKs can appear in people in their 30s and 40s.

A weakened immune system also raises the risk. For example, people who have had an organ transplant are more likely to develop AKs because their immune systems are less able to recognize and fight off skin cell changes.

Most of the time, dermatologists can diagnose an AK just by looking at and feeling the spot. Sometimes a biopsy (a small skin sample) is needed. “If the patient says the lesion is tender, or it’s been bleeding, those are reasons to biopsy it,” says Dr. Suozzi. A biopsy may also be done if a spot doesn’t respond to treatment, to check for something more serious, or to confirm the diagnosis.

A dermatologist’s examination also helps because AKs can look like other skin conditions, including eczema, other rashes (dermatitis), and inflamed hair follicles (folliculitis).

Treatment depends on how many AKs you have and where they are on your body.

If you have one or a few AKs, your dermatologist can destroy each spot. This is the most common treatment. The usual method is cryotherapy, which uses extreme cold. Your dermatologist applies liquid nitrogen to the spot. It stings for a few minutes. Within a day or two, a crust or small blister forms, and the skin heals in two to three weeks.

A dermatologist may also scrape off a spot and seal it with heat, or treat it with a cream.

If you have many AKs in one area, such as your whole face, chest, or scalp, treating each spot isn’t practical, Dr. Suozzi says. This is when treatments that cover the whole area, called field therapy, can help.

Prescription creams and gels, applied at home, play a major role. Options include:

• Fluorouracil (also called 5-FU): This cream can cause redness, irritation, and peeling during treatment. These effects go away after treatment ends.

• Imiquimod: This cream helps your immune system attack precancerous skin cells.

• Diclofenac: This gel is less irritating than other options, but it may not work as dramatically.

• Tirbanibulin (Klisyri): This newer cream is applied for about five days.

Your dermatologist can explain how long to use a product and what skin reactions to expect.

Two additional treatments are done in a doctor’s office to treat widespread AKs: photodynamic therapy (PDT) and lasers. With photodynamic therapy, your dermatologist applies a light-sensitive medicine to the whole area, then shines a red or blue light on it to destroy the damaged cells all at once.

“When we treat a patient with field therapy, we’re ‘weeding the garden,’” says Dr. Suozzi. “Since we aren’t necessarily able to get rid of all those weeds, they eventually come back. Treatment may need to be repeated, say, once a year, to maintain the clinical benefit.”

Treating an AK is one part of a longer-term plan. Because AKs are a sign of sun damage, new ones can appear over time, and your dermatologist may recommend regular skin checks.

“When we talk to a patient about managing their AK, the focus isn’t just treating that single lesion on the skin,” says Dr. Christensen. “It’s about counseling them and managing their risk for skin cancer five or 10 years later.”

Most AKs can be treated by a general dermatologist. Yale Medicine dermatologists also care for many people who are at high risk for skin cancer, including people referred by other dermatologists for more complex cases. Dr. Suozzi says Yale Medicine’s medical and procedural dermatologists work closely together to manage these complex cases.

Dr. Christensen also helped develop a scoring tool that estimates skin cancer risk based on how many AKs are on your face. Yale Medicine dermatologists use it to decide who will benefit most from treatment.

For AKs that haven’t responded to other treatments, Yale Medicine also offers photodynamic therapy with both red and blue light, a wide range of laser treatments, and laser-assisted drug delivery.

Regular sunscreen use can help AKs shrink or go away. The American Academy of Dermatology recommends about a shot glass full of sunscreen for your entire body. For your head and neck, “We usually advise that people use a half teaspoon or quarter-size amount and then reapply every two hours,” says Dr. Suozzi.

A broad-spectrum sunscreen with a sun protection factor (SPF) of 30 blocks about 97% of the ultraviolet B (UVB) rays that cause sunburn. That’s enough for routine use. A higher SPF adds only a little more protection, and the product tends to be thicker, whiter, and harder to wear. The most common reason sun protection fails isn’t an inadequate SPF number—it’s not reapplying.

Sun-protective clothing helps, too. Dr. Suozzi notes that after the face, the forearms are one of the most common places AKs appear. Not all fabric blocks ultraviolet (UV) rays, so check the garment’s ultraviolet protection factor (UPF).

If you notice a rough, scaly spot on your face, arms, or another area that gets a lot of sun, and it doesn’t go away after about a month, schedule an appointment with a dermatologist. It’s never too late to protect your skin or seek treatment.