Photo illustration of Actinic Keratosis

Actinic keratoses generally appear as rough, red/brown, scaly macules or papules on the skin. They start to appear usually about age 30 or older.

Actinic keratoses (AKs) are A premalignant neoplasm of the epidermis caused by excessive exposure to sunlight and manifesting as an ill-marginated, erythematous, scaling, rough papule or patch that form on sun exposed areas of the skin, including the scalp, face, forearms, and back of the hands.

Actinic keratoses are usually scaly, feel like sandpaper to the touch, and range in color from skin-toned to reddish-brown " AK are more easily felt than seen, as their overlying scale is thick and firmly adherent".  Actinic keratoses may be as small as the head of a pin or as large as a quarter (or bigger, if left untreated).

Actinic keratoses on the scalp

Actinic keratoses are most common in individuals over 40 years old with fair skin and years of excessive sun exposure. However, even younger people (including those with dark skin) can develop actinic keratoses if they live in very sunny climates.

Lesions are occasionally tender to palpation. Fair-skinned persons, who burn easily and tan poorly, are most commonly affected. A small percentage of AK on non-mucosal skin can progress to skin cancer squamous cell carcinoma. Ultraviolet light exposure induces formation of the lesions.