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-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?
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)
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 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.
- 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 color (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), imiquimod (Aldara), ingenol mebutate (Picato), and diclofenac (Solaraze).
- 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 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 30.
- Avoid tanning booths and sunlamps, which emit UV radiation
and can cause skin damage and increase the risk of skin cancer.
- Seborrheic Keratoses
- Skin Cancer, Melanoma
- Skin Cancer, Nonmelanoma
- Skin Changes
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.
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.