Actinic keratosis

Alternative Names

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

Definition of Actinic keratosis

Actinic keratosis is a precancerous growth on the skin.

Causes, incidence, and risk factors

Actinic keratosis is caused by sun exposure.

Signs and tests

The health care provider makes the diagnosis based on the appearance of the skin growth. A may reveal any cancerous changes, if they occur.


Because actinic keratoses are precancerous changes, have them examined promptly. Follow your health care provider’s advice for treatment.

Expectations (prognosis)

Actinic keratosis itself is (harmless), but it may on rare occasions develop into skin .


Michael Lehrer, MD, Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network; Linda Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. – 12/11/2009

Actinic keratosis on the arm
Actinic keratosis - close-up
Actinic keratosis on the forearms
Actinic keratosis on the scalp
Actinic keratosis - ear

ADAM Medical Encyclopedia

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