What is actinic keratosis, and what causes it?
Actinic keratosis, also called solar or senile keratosis, is a precancerous skin condition that develops in sun-exposed skin, especially on the face, hands, forearms, and the neck. It is seen most often in pale-skinned, fair-haired, light-eyed people, beginning at age 30 or 40 and becoming more common with age.
What are the symptoms?
Actinic keratoses are small and noticeable red, brown, or skin-colored patches that don't go away. They commonly occur on the head, neck, or hands but can be found on other areas of the body. Usually more than one is present. They may:
- Have a rough texture.
- Itch, burn, or sting.
- Range in size from 1 mm to 3 mm or larger (about the size of a small pea).
- Be numerous, with several patches close together.
- Be surrounded by red, irritated skin.
Actinic keratosis needs to be evaluated by a doctor, especially if the keratoses become painful, bleed, become open sores, become infected, or increase in size.
How is actinic keratosis diagnosed?
Actinic keratosis is diagnosed through a skin examination. Your doctor may use a bright light or magnifying lens to look for growths, moles, or lesions. The scalp is examined by parting the hair. If there is a possibility of cancer, your doctor may take a sample of your skin and test (biopsy) it.
How is it treated?
Early treatment of actinic keratosis is recommended to stop the possible progression to a type of skin cancer (squamous cell carcinoma). Treatment may include:
- Freezing the skin growth with liquid nitrogen (cryotherapy) to destroy it. Cryotherapy can cause mild pain that can last up to 3 days. Healing generally takes 7 to 14 days, and there is little or no scarring, though some people with darker skin have permanent skin color lightening. This procedure can be done in your doctor's office.
- Scraping and using electric current (curettage and electrosurgery). The skin is numbed, and the growth is scraped off using a spoon-shaped instrument (curette). After scraping, electrosurgery may be done to control bleeding and destroy any remaining abnormal cells. Curettage is a quick treatment, but it can cause scarring. Sometimes a thick scar, or keloid, develops after curettage treatment. A keloid can be itchy or grow larger over time but it doesn't require medical treatment.
- Medicines that are put on the skin, such as fluorouracil (5-FU), imiquimod cream (Aldara), and 3% diclofenac gel (Solaraze).
- Photodynamic therapy (PDT) using aminolevulinic acid (ALA). PDT is a treatment that uses light combined with a medicine that is put on the skin (ALA). The light causes the medicine to destroy the actinic keratosis. One study found that treatment with PDT and ALA left the skin looking better than treatment with cryotherapy.1
Will actinic keratosis progress to cancer?
If you have actinic keratosis, you may have an increased risk of developing squamous cell carcinoma. There is no way to determine whether actinic keratosis will progress to squamous cell carcinoma or how fast this might occur. Keratoses on the ear and lip are at the highest risk of developing into cancer because of the sensitivity of the ear and lip to sun exposure.
How can I prevent actinic keratosis?
You can help prevent actinic keratosis by staying out of the sun and using sunscreen when you are in the sun. You should also examine your skin for the condition and other suspicious growths once a month, especially if you spend a lot of time in the sun.
To protect your skin:
- Limit your exposure to the sun, especially from 10:00 a.m. to 4:00 p.m., the hours of peak ultraviolet (UV) exposure.
- Wear protective clothing, including a wide-brimmed hat, a long-sleeved shirt, and pants.
- Wear sunglasses that block out UV rays.
- Use a sunscreen that blocks ultraviolet rays (both UVA and UVB) and has a sun protection factor (SPF) of at least 15 every day, all year, even when it is cloudy.
- Avoid tanning booths and sunlamps, which emit UV radiation and can cause skin damage and increase the risk of skin cancer.
- Chong AH, Sinclair R. (2006). Actinic keratoses. In MG Lebwohl et al., eds., Treatment of Skin Disease, 2nd ed., pp. 14–16. London: Mosby Elsevier.
Other Works Consulted
- Duncan KO, et al. (2008). Actinic keratosis section of Epithelial precancerous lesions. In K Wolff et al., eds., Fitzpatrick's Dermatology in General Medicine, 7th ed., vol. 1, pp. 1007–1015. New York: McGraw-Hill Medical.
Last Updated: October 14, 2008