What is actinic keratosis, and what causes it?
Actinic keratosis, also called solar keratosis, is a skin growth 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-coloured 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?
Your doctor may recommend one of these treatments:
- Freezing the skin growth with liquid nitrogen (cryosurgery) to destroy it. Cryosurgery (also called cryotherapy) can cause mild pain that can last up to 3 days. Healing typically takes 7 to 14 days. And there is little or no scarring, though some people with darker skin have permanent skin colour 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.
- Shaving the growth with a surgical blade (shave excision). This is done to remove the growth and check the cells for basal or squamous cell carcinoma. Healing typically takes 7 to 14 days. There may be some scarring and changes in the colour (pigment) of your skin.
- Peeling the skin with chemicals (chemical peel). This is done so new skin can grow and replace damaged skin.
- Resurfacing the skin with laser (laser resurfacing). An intense beam of light from a laser (such as the carbon dioxide or CO2 laser) is used to destroy the top layer of skin. As the treated area heals, new skin grows to replace the damaged skin.
- Treating the skin with medicines that are put on the skin, such as fluorouracil (5-FU) and imiquimod (Aldara).
- Using medicine and light to kill cells ( photodynamic therapy, or PDT). PDT uses medicine, such as aminolevulinic acid (ALA), that is put on the skin and then activated with light. The light causes the medicine to destroy the actinic keratosis.
Will actinic keratosis progress to cancer?
Actinic keratosis may turn into skin cancer, but this isn't common. There is no way to find out 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 11 a.m. to 3 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 30.
- Avoid tanning booths and sunlamps, which emit UV radiation and can cause skin damage and increase the risk of skin cancer.
Other Works Consulted
- Duncan KO, et al. (2012). Epithelial precancerous lesions. In LA Goldman et al., eds., Fitzpatrick's Dermatology in General Medicine, 8th ed., vol. 1, pp. 1261–1283. New York: McGraw-Hill.
- Kose O, et al. (2008). Comparison of the efficacy and tolerability of 3% diclofenac sodium gel and 5% imiquimod cream in the treatment of actinic keratosis. Journal of Dermatological Treatment, 19(3): 159–163.
Current as of: October 31, 2019
Author: Healthwise Staff
Medical Review: E. Gregory Thompson, MD - Internal Medicine
Brian O'Brien, MD, FRCPC - Internal Medicine
Adam Husney, MD - Family Medicine
Martin J. Gabica, MD - Family Medicine
Amy McMichael, MD - Dermatology