What are actinic keratoses?

Actinic keratoses (AKs) are considered the earliest stage in the development of skin cancer (pre-cancers). They are common lesions of the epidermis (the outermost layer of the skin) and are caused by long-term ultraviolet sunlight exposure. AKs are most likely to appear after age 40; however, in geographic areas with year-round, high-intensity sunlight such as here in south Florida, AKs have even been found in teenagers. Half of all older, fair-skinned persons who live in hot, sunny areas have AKs. The most significant predisposing factor to AKs is fair skin and long-term sun exposure.

Chronic ultraviolet sun exposure causes skin cells to change size, shape, and the way they are organized. The skin cells affected in AKs are the keratinocytes. Keratinocytes are the tough-walled cells that make up 90 percent of the epidermis and give the skin its texture.

Changes in keratinocytes can be seen when the skin becomes rough, scaly, or mottled and develops bumps or small, horn-like growths. Further changes in cell growth can turn AKs into squamous cell carcinoma, a type of skin cancer.

What do actinic keratoses look like?

Actinic keratoses are found on chronically sun-exposed skin, most commonly on a fair-skinned person, middle-aged or older. They are commonly found on the sides of the forehead, the ears, the scalp of bald men, and the backs of the hands. The typical AK lesion is a dry, scaly, rough, skin-colored to reddish-brown "bump" on the skin. It may range from the size of a pinhead to larger than a quarter. Skin-colored AK lesions may be noticed more by touch because they tend to have a sharp, hard scale and feel like sandpaper. They are often sensitive or "touchy." Wrinkling, furrowing, and other signs of sun damage may be present with AK lesions.

Sometimes, the skin cells making up an AK lesion undergo abnormal growth and become a "cutaneous horn." The cutaneous horn gets its name from its appearance because it can look like the horn of an animal. The size of a horn may vary from a pinhead to a pencil eraser, and its shape may be straight or curved. The external ear is a common site for a cutaneous horn.

An actinic keratosis can also appear as a scaling lesion on the lower lip that dries and cracks open. An AK at any location may at times seem to disappear for weeks or months and then return at the same place. If it is picked off, it grows back.

Treatment of Actinic Keratoses

At Miramar Dermatology/Skin and Cancer Associates, the types of treatment for actinic keratoses are cryosurgery, surgical removal and biopsy, topical chemotherapy, and photodynamic therapy. Other surgical options that may be suggested include chemical peels and laser skin resurfacing.

Cryosurgery - Liquid nitrogen "freezes" surface skin. It really is a localized frost bite. A blister usually forms and then flakes off and is replaced by new skin. Skin redness is the chief side effect. Cryosurgery is the most commonly used treatment when there are one to 20 AKs to treat.

Topical Chemotherapy - A topical anti-cancer cream or lotion (5-fluorouracil or imiquimod) is applied to the skin to treat and bring out actinic keratosis lesions. A localized red spot may remain for a while at the site of a treated AK. This form of treatment is used when there is a large sun-damaged area with many pre-cancers present.

Photodynamic Therapy - A natural chemical, aminolevulinic acid, is applied to the skin and allowed to penetrate for 30 to 60 minutes. Then the skin is exposed to a specific wavelength of intense pulsed light (IPL). This form of laser light treatment activates the chemical to destroy the actinic keratoses. Localized red areas develop in treated regions, which fade after several days. A secondary benefit to this treatment is that the face is rejuvenated. Brown marks and red vascular marks lighten or disappear altogether, making your skin look years younger.

Chemical Peeling - A chemical solution is applied to the skin by a physician or a physician assistant. This causes the skin to peel off over a period of days. As the treated skin peels, new skin forms to replace it. Drs. Gottlieb and Goldman will select a chemical solution to accomplish a mild, medium, or deep peel. The principal side effect is redness and swelling of skin for a period of time after the treatment.

Laser Skin Resurfacing - A series of treatments with a carbon dioxide laser removes surface skin to a desired depth. Post-treatment skin redness is the principal side effect. A week or two of healing is needed.

Research and development of other treatments for treating actinic keratosis is an ongoing process. Rest assured that at Miramar Dermatology/Skin and Cancer Associates, we stay on top of the outcomes of all of the research.

Treatment options are fully and openly discussed with you during your visit. After AKs are removed, the new skin must be protected from new solar damage by a program of skin care that includes sun protection utilizing an SPF of 30 or higher.

Prevention of Actinic Keratoses

Prevention of AKs should begin early in life. Sun damage to unprotected skin begins in childhood and puts the child at risk for actinic keratoses and skin cancer later in life. However, it is never too late to initiate prevention of new actinic keratosis lesions in adulthood.

The basics of prevention are:

• Avoid excessive exposure to sunlight during peak sunlight hours (10 a.m. to 4 p.m.).
• Wear clothing that covers arms and legs, and wear a wide-brimmed hat.
• Use a sunscreen with a sun protection factor (SPF) of 30 or higher daily. Apply at least 20 minutes prior to sun exposure for maximum sun protection.
• Select a broad-spectrum sunscreen that provides both UVA and UVB protection, and reapply sunscreen every 1.5 hours when outdoors, even on cloudy days. You can find the great SPF Aspen Zheng Doctor’s Skin Care product at Miramar Dermatology/Skin and Cancer Associates.