Actinic Keratosis: What It Is and What to Do About It

Also called solar keratosis, actinic keratosis (AK) is a skin condition caused by UV exposure and affects an estimated 58 million Americans. While actinic keratosis is not skin cancer, it is classified as a precancerous lesion, meaning it has the potential to turn into skin cancer if left untreated. Additionally, many people are bothered by the appearance of AKs, especially when they occur on the face. Here, we discuss what actinic keratosis looks like, how it’s diagnosed, and the best treatment options.

Actinic keratosis is a rough, scaly patch on the skin that develops after years of exposure to UV radiation from the sun or tanning beds. It forms when UV radiation damages the DNA in skin cells called keratinocytes. This damage causes these cells to grow abnormally, creating rough patches that often recur in the same spot, even if scraped or picked off. However, you should avoid picking these spots and should see a dermatologist if you suspect you have actinic keratosis.

AK lesions most often appear on sun-exposed areas like the face, scalp, ears, nose, neck, arms, and backs of the hands. While their appearance can vary, they generally share a few common features:

• Rough or sandpaper-like texture

• A flat or slightly raised patch or bump

• Red, pink, or skin-colored

• A scaly or crusted surface

There are also different clinical grades of actinic keratosis, generally relating to the severity of the lesion.

• Grade I (mild). You may notice slightly rough skin, but AKs at this stage are often felt more than seen.

• Grade II (moderate). AKs are more visible and scaly and may be red or inflamed.

• Grade III (severe) . Thick, crusted, or wart-like lesions are common at this grade.

• Grade IV (hypertrophic or proliferative). This is the most advanced stage of actinic keratosis. Very thick, nodular, or horn-like lesions can develop that may closely resemble squamous cell carcinoma and require biopsy to rule out cancer.

The root cause of AK is cumulative damage from UV radiation, which leads to mutations in the DNA of keratinocytes in the epidermis. When these cells begin to grow irregularly, they form actinic keratoses. The risk increases with age and years of sun exposure.

People most prone to developing AK include:

• Those with fair skin, light eyes, and blond or red hair.

• Those with a history of frequent or intense sun exposure.

• People who use tanning beds.

• Those with weakened immune systems.

• Older adults, particularly those over age 50.

No, actinic keratosis itself is not cancer. However, it is considered a precancer because it can turn into squamous cell carcinoma over time. While there is a fairly low conversion rate of AK to SCC – estimated around 1% per year – most cases of SCC begin as actinic keratosis (3). Because of this, and because there is no way to predict which lesions will become cancerous, all AK lesions should be diagnosed and treated by a dermatologist.

Your dermatologist will examine your skin, noting the lesion’s appearance and texture to determine if it could be actinic keratosis. In some cases, this is sufficient to diagnose AK. In other cases, particularly in more advanced stages, a skin biopsy may be necessary. This involves removing a small sample of the lesion, which is then examined under a microscope. The biopsy not only confirms the diagnosis but also helps to determine the severity or grade of the lesion so your dermatologist can determine the best course of action.

If you have a history of multiple AKs or skin cancer, see your dermatologist for a full-body exam twice per year to catch any other suspicious lesions early.

The best treatment for actinic keratosis will depend on its severity and location. The most common treatment options for AK lesions include:

1. Cryotherapy with Liquid Nitrogen-
   Cryotherapy with liquid nitrogen freezes the actinic keratosis lesion causing the abnormal cells to blister and fall away as the skin heals.
2. Excision-
   Excision is the surgical removal of the lesion often used in cases where there may be a high risk of developing into skin cancer.
3. Laser Treatments-
   Laser treatments use laser resurfacing to remove the outer layer of damaged skin and promote the growth of new healthy skin.
4. Photodynamic Therapy with Levulan or ALA (Aminolevulinic Acid)-
   Photodynamic therapy involves applying a photosensitizing agent such as Levulan or ALA to the skin followed by exposure to a special light. This activates the medication to destroy abnormal cells with minimal damage to surrounding tissue.
5. Shave Curettage and Electrocautery-
   Shave curettage and electrocautery involves shaving or scraping off the lesion followed by cauterization to stop bleeding and destroy remaining abnormal cells.
6. Topical Prescription Treatments-
   Topical treatments include prescription creams like 5-fluorouracil, imiquimod, and diclofenac which target abnormal cells and trigger immune responses to clear lesions. These medications can be particularly useful for treating multiple lesions and may be combined with physical methods for more effective results.

New actinic keratosis lesions can be preventable with proper sun protection habits:

• Wear at least SPF 15 every day; SPF 30 when you will be outdoors.

• Reapply sunscreen every two hours or after swimming or sweating.

• Wear sun-protective clothing such as wide-brimmed hats, sunglasses, or even UV-protecting clothing.

• Try to stay in the shade as much as possible, especially during the peak sunlight hours of 10am to 4pm.

The best way to make sure you will use sunscreen every day is to choose a product that feels good on your skin and doesn’t contribute to breakouts, greasiness, or other unwanted effects. To do this, choose a sunscreen that is a match for your skin type. Some of our favorites include:

Rough, scaly patches or bumps on the skin could be actinic keratosis. While this is not a type of skin cancer itself, it can turn into squamous cell carcinoma over time if left untreated. If you think you might have an AK lesion, make an appointment with your dermatologist for an accurate diagnosis and customized treatment plan. To prevent AKs and lower the risk of developing skin cancer, wear SPF every day.

1. Jeffes, E.W.B., Tang, E.H. Actinic Keratosis. Am J Clin Dermatol 1 , 167–179 (2000). https://doi.org/10.2165/00128071-200001030-00004
2. Salasche, S. J. (2000). Epidemiology of actinic keratoses and squamous cell carcinoma. Journal of the American Academy of Dermatology, 42(1), S4-S7.
3. Schauder, D. M., Kim, J., & Nijhawan, R. I. (2020). Evaluation of the use of capecitabine for the treatment and prevention of actinic keratoses, squamous cell carcinoma, and basal cell carcinoma: a systematic review. JAMA dermatology, 156(10), 1117-1124.
4. Ackerman, A. B., & Mones, J. M. (2006). Solar (actinic) keratosis is squamous cell carcinoma. British Journal of Dermatology, 155(1), 9-22.
5. Gutzmer, R., Wiegand, S., Kölbl, O., Wermker, K., Heppt, M., & Berking, C. (2019). Actinic Keratosis and Cutaneous Squamous Cell Carcinoma: Treatment Options. Deutsches Ärzteblatt International, 116(37), 616.