Actinic keratosis, also called solar or senile keratosis, is a precancerous skin condition that develops in sun-exposed skin, especially on the face, hands, forearms, and neck. It occurs most often in pale-skinned, fair-haired, light-eyed people beginning at age 30 or 40.

Actinic keratoses are persistent, noticeable, small red, brown, or skin-colored patches that may become scaly, scabbed, or crusted. The patches may itch, burn, or sting.

If the affected skin is protected from the sun, the patches may grow smaller and disappear. If sun exposure continues, they may eventually change into skin cancers (squamous cell carcinoma). Early treatment of actinic keratoses—by cryotherapy (freezing), electrosurgery (burning), curettage (scraping), photodynamic therapy with ALA (a treatment combining light and medicine), or medicines that are put on the skin—can prevent progression to squamous cell carcinoma.