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Actinic Keratosis

An early warning sign of skin cancer is the development of an actinic keratosis. Actinic keratoses are precancerous skin lesions that result from chronic sun exposure. They are typically < 0.5cm in diameter, pink or red in color and rough or scaly to the touch. They occur on sun-exposed areas of the skin (face, scalp, ears, backs of hands or forearms). Actinic keratoses may start as small, red, flat spots but grow larger and become scaly or thick, if untreated. Sometimes they are easier to feel than to see. There may be multiple lesions next to each other.

Early treatment of actinic keratoses may prevent their change to cancer. These precancerous lesions affect more than 10 million Americans. People with one actinic keratosis usually develop more. Up to 1% of these lesions can develop into a squamous cell cancer.

Actinic keratoses are most common in people older than 40, but can also appear in younger individuals with extensive sun exposure. Because they can turn cancerous affected areas should be regularly examined and treated by a primary care physician or dermatologist.

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Images (click on an image for a larger view)

Actinic keratosis
Pink scaly skin lesion on sun-damaged cheek.
  actinic keratosis

Actinic keratoses
Multiple pink skin lesions on the back of a hand.
  actinic keratoses

actinic keratoses

Microscopic view of an Actinic Keratoses

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Last reviewed by UCSF Dermatologists
February 16, 2006

This information is for educational purposes only and is not intended to replace the advice of your doctor or health care provider. We encourage you to discuss with your doctor any questions or concerns you may have.
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