Actinic keratosis is a small, rough, raised area found on areas of your skin that have often been exposed to the sun for a long period of time.

Some actinic keratoses may develop into a type of skin cancer.

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

Actinic keratosis is caused by exposure to sunlight.

You are more likely to develop this if you:

• Have fair skin, blue or green eyes, or blond or red hair
• Had a kidney or other transplant
• Take medicines that suppress the immune system
• Spend a lot of time each day in the sun (for example, if you work outdoors)
• Had many, severe sunburns early in life
• Are older

Actinic keratosis is usually found on the face, scalp, back of the hands, chest, or places that are often in the sun.

• The skin changes begin as flat and scaly areas. They often have a white or yellow crusty "scale" on top.
• The growths may be gray, pink, red, or the same color as the skin. Later they may become hard and wart-like or gritty and rough.
• The areas may be easier to feel than see. 

Your doctor or nurse will look at your skin to diagnose this condition. A skin biopsy may be done to see if it is cancer.

Some actinic keratoses become squamous cell skin cancer. Have all skin growths looked at by a doctor as soon as you find them. Your doctor will tell you how to treat it.

Growths may be removed by:

• Burning (electrical cautery)
• Scraping away the lesion and using electricity to kill any remaining cells (called 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)

If you have many of these skin growths, your doctor may recommend:

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

A small number of these skin growths turn a type of skin cancer called squamous cell carcinoma.

Call your health care provider if you see or feel a rough or scaly spot on your skin, or if you notice any other skin changes.

The best way to lower your risk of actinic keratosis and skin cancer is to learn how to protect your skin from sun and ultraviolet (UV) light.

Things you can do to lower your exposure to sunlight include:

• Wear clothing such as hats, long-sleeved shirts, long skirts, or pants.
• Try to avoid being in the sun 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 things to know about sun exposure:

• 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.

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

Soyer PH, Rigel DS, Wurm E MT: Bolognia JL, Jorizzo JL, Schaffer JV, et al, eds. Dermatology. 3rd ed. Philadelphia, Pa: Mosby Elsevier; 2012:chap 108.