Actinic keratosis

Definition

Actinic keratosis is a small, rough, raised area found on skin that has been exposed to the sun over a long period of time.

Over many years, some actinic keratoses may develop into a type of skin cancer.

Alternative Names

Solar keratosis; Sun-induced skin changes - keratosis; Keratosis - actinic (solar)

Causes, incidence, and risk factors

Actinic keratosis is caused by sun exposure, but it takes many years or decades to develop.

Risk factors for actinic keratosis include:

• Having fair skin, blue or green eyes, or blond or red hair
• History of kidney or other solid organ transplant (people who take medicines that suppress the immune system)
• Long-term, daily sun exposure (for example, if you work outdoors)
• Multiple, severe sunburns early in life
• Older age

Symptoms

Actinic keratosis is usually found on the face, scalp, back of the hands, chest, or other sun-exposed areas.

They may be gray, pink, red, or the same color as the skin. Often, they have a white or yellow scale on top.

• They begin as flat and scaly areas
• Later they develop a hard and wart-like or gritty, rough, and "sandpapery" surface -- may develop a horn-like texture

The skin lesion may be easier to feel than to see.

Signs and tests

The health care provider makes the diagnosis based on the appearance of the skin growth. A skin biopsy may be done for larger and thicker actinic keratoses to make sure no cancer is present.

Treatment

Because about 5% of actinic keratoses go on to develop into squamous cell skin cancer, have them examined promptly. Follow your health care provider's advice for treatment.

Growths may be removed by:

• Burning (electrical cautery)
• Scraping away the lesion and using electricity to kill any remaining cells (caled curettage and electrodesiccation)
• Cutting the tumor out and using stitches to place the skin back together (called excision)
• Freezing (cryotherapy, which freezes and kills the cells)

When many actinic keratoses are found, treatments that cause irritation and redness over a larger area are used:

• A laser treatment called photodynamic therapy
• Chemical peels
• Creams such as 5-fluorouracil (5-FU) and imiquimod

Support Groups

Expectations (prognosis)

Actinic keratosis itself is harmless ( benign), but about 5% develop into skin cancer.

Removal of the growth is usually effective.

Complications

• Irritation and discomfort of the skin growth
• Scarring from the treatment
• Squamous cell carcinoma

Calling your health care provider

Call for an appointment with your health care provider if areas of persistent roughness or scaliness develop in sun-exposed skin.

Prevention

Reduce sun exposure and protect your skin from the sun:

• Wear protective clothing such as hats, long-sleeved shirts, long skirts, or pants.
• Try to avoid sun exposure during midday, when ultraviolet light is most intense.
• Use high-quality sunscreens, preferably with a sun protection factor (SPF) rating of at least 15. Pick a sunscreen that blocks both UVA and UVB light.
• Apply sunscreen before going out into the sun, and reapply often.
• Use sunscreen year-round, including in the winter.
• Avoid sun lamps, tanning beds, and tanning salons.

Other important sun safety facts to keep in mind:

• Sun exposure is stronger in or near surfaces that reflect light, such as water, sand, concrete, and areas painted white.
• Sun exposure is more intense at the beginning of the summer.
• Skin burns faster at higher altitudes.

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References

Habif TP, ed. Clinical Dermatology. 5th ed. Philadelphia, Pa: Mosby Elsevier;2009:pp 812-818.

Ibrahim SF, Brown MD. Actinic keratoses. In: Lebwohl M, ed. Treatment of Skin Disease: Comprehensive Therapeutic Strategies. 3rd ed. Philadelphia, Pa: Saunders Elsevier; 2009.