Bruce P.Robinson, MD
Seborrheic Keratoses are often confused with warts or moles, but they are quite different. Seborrheic Keratoses are non-cancerous growths of the outer layer of skin. There may be just one growth or many which occur in clusters. They are usually brown, but can vary in color from light tan to black and range in size from a fraction of an inch in diameter to larger than a half-dollar. A main feature of Seborrheic Keratoses is their "waxy, pasted-on" appearance. They sometimes look like a dab of warm brown candle wax that has dropped onto the skin or like barnacles attached to the skin.
The exact cause of seborrheic keratoses is unknown; however, they seem to run in families. They are not caused by sunlight and can be found on both sun-exposed and non sun-exposed areas. Seborrheic Keratoses are more common and numerous with advancing age. Although Seborrheic Keratoses may first appear in one spot and seem to spread to another, they are not contagious.
Anyone may develop Seborrheic Keratoses. Some people develop many over time, while others develop only a few. As people age, they may simply develop more. Children rarely develop Seborrheic Keratoses. Seborrheic Keratoses may erupt during pregnancy, following estrogen therapy, or in association with other medical problems.
Seborrheic Keratoses are most often located on the chest or back, although they also can be found on the scalp, face, neck, or almost anywhere on the body. The growths usually begin one at a time as small, rough, itchy bumps which eventually thicken and develop a warty surface.
Seborrheic Keratoses are benign (non-cancerous) and are not serious. Unless they develop suddenly, they do not indicate a serious health problem. They may be unsightly, especially if they appear on the face. Removal may be recommended if they become large, irritated, itch, or bleed easily. A Seborrheic Keratosis may turn black and may be difficult to distinguish from skin cancer. Such a growth must be removed and biopsied (studied under a microscope) to determine if it is cancerous or not.
Creams, ointments, or other medication can neither cure nor prevent Seborrheic Keratoses. Most often Seborrheic Keratoses are removed by cryosurgery, curettage, or electrosurgery. Cryosurgery, liquid nitrogen, a very cold liquid gas, is applied to the growth with a cotton swab or spray gun to "freeze" it. A blister may form under the growth which dries into a scab-like crust. The Keratosis usually falls off within a few weeks. Occasionally, there will be a small dark or light spot that usually fades over time.
Curettage: The keratosis is scraped from the skin. An injection or spray is first used to anesthetize (numb) the area before the growth is removed (curetted). No stitches are necessary, and the minimal bleeding can be controlled by applying pressure or the application of a blood-clotting chemical.
Electrosurgery: The growth is anesthetized (numbed) and an electric current is used to burn the growth which is then scraped off.
