What is an actinic keratosis? Dermatologist explains common precancerous skin lesion

Actinic keratoses are very common precancerous skin lesions caused by long-term sun exposure. Dermatologists often find actinic keratoses during skin checks.

An actinic keratosis is not cancer. But if left untreated, over time, it can turn into skin cancer. Here, I’ll answer common questions about actinic keratoses, including what causes them and how they’re treated.

What causes actinic keratoses?

Actinic keratoses are caused by long-term, excessive exposure to ultraviolet (UV) rays. This can come from sunlight or tanning beds. UV radiation damages the DNA of skin cells. Over time, as the damage builds up, the cells start to grow abnormally.

Because they are caused by too much chronic UV exposure, actinic keratoses typically develop on skin that gets a lot of sun, such as your:

• Scalp
• Forehead
• Ears
• Face
• Cheeks
• Back of the arms
• Back of the hands

You may also get actinic keratoses on your back if you are in the sun a lot without a shirt, or your lower legs if you wear shorts often.

Risk factors for actinic keratoses include:

• A job or lifestyle that causes you to spend a lot of time outdoors in the sun
• Fair skin
• Older age
• A suppressed or weakened immune system

What do actinic keratoses look and feel like?

Actinic keratoses are small lesions on the skin. They typically look like small pink spots. They have a rough scale that makes them feel gritty, like sandpaper. 

Actinic keratoses are often easier to feel than see when they are very small.

What are the symptoms of actinic keratoses?

Sometimes, actinic keratoses can cause mild itching or stinging, or they can feel sensitive to touch.

When a scaly spot may not be an actinic keratosis

Actinic keratoses typically do not:

• Cause a lot of pain
• Grow or thicken quickly
• Form sores, especially ones that never heal
• Bleed
• Become raised fleshy or firm bumps

If you have any of the above symptoms, they may be signs of something more serious, like skin cancer. See a doctor as soon as possible to get checked out.

How is an actinic keratosis diagnosed?

An actinic keratosis is usually diagnosed clinically. This means a dermatologist will physically examine you and then diagnose a spot as an actinic keratosis based on how the spot looks and feels. You usually will not need a biopsy.

How often does an actinic keratosis turn into cancer?

An actinic keratosis is not cancer. But it is a sign that UV damage has occurred to skin cells in the area. It is considered precancerous. While most actinic keratoses do not turn into cancer, it’s estimated that 1% to 10% can develop into squamous cell carcinoma, the second most common type of skin cancer.

How are actinic keratoses treated?

There are several ways to treat acinic keratoses. At MD Anderson, we may use any of the following treatments.

Cryotherapy

Liquid nitrogen is sprayed onto individual lesions to freeze them. The frozen skin cells are damaged and die over the next few days. The area may blister or scab over, and then new healthy skin grows in.  

Topical medications

There are several topical creams and gels approved by the Food and Drug Administration (FDA) to treat actinic keratoses. Since we know actinic keratoses are a sign of underlying sun damage to an entire area of skin, these creams and gels are a great option to field treat areas where there are often a lot of actinic keratoses – not just one isolated spot. The topical medications may need to be applied to the skin for different lengths of time. They get absorbed in the damaged skin cells and then either destroy them or tell your immune system to clear them away. Topical medications may cause some temporary redness or inflammation in your skin while they are working.

Here at MD Anderson, dermatologist Mackenzie Wehner, M.D., is leading a clinical trial studying a combination cream to treat actinic keratoses. The combination cream is used for just a few days compared to current treatments that must be used for several weeks. This could reduce how long patients experience treatment side effects.

Photodynamic therapy

During this procedure, we apply a special medicine to your skin and then shine a specific kind of light on it. The light activates the medicine and destroys the damaged cells, so healthier skin can grow back in. You may have some inflammation on the skin while it heals. It is a great option to treat larger areas with many actinic keratoses.

At MD Anderson, we perform photodynamic therapy in our Mohs Center. 

Caring for the area during treatment

With gentle skin care, treated areas typically return to normal within a few days after completing treatment. It’s important to protect the area from the sun during treatment to help get the best response.

What happens if you don’t treat an actinic keratosis?

If you don’t treat actinic keratoses, some may go away on their own, some will stay the same, and some can slowly turn into skin cancer over time.

Since there is no way to know which ones will eventually change into skin cancer, treating them early lowers your cancer risk. So, while most actinic keratoses are harmless, we treat them to be safe.

How can you prevent actinic keratoses?

You can help prevent actinic keratoses by protecting your skin from harmful UV radiation. Follow these tips:

• Seek shade between 10 a.m. and 4 p.m., when the sun’s rays are strongest.
• Use sunscreen and lip balm with SPF 30 or higher.
• Wear a wide-brimmed hat, protective clothing and UV-protective sunglasses.
• Avoid using tanning beds.

Finally, pay attention to changes in your skin. If you see or feel anything unusual, see your doctor to get it checked out. Actinic keratosis is very treatable.

Saira George, M.D., is a dermatologist at MD Anderson in Sugar Land.

Request an appointment at MD Anderson online or call 1-877-632-6789.