Although seborrheic keratoses (seb-o-REE-ick ker-ah-TOE-sees) are often confused with warts, they are quite different. Seborrheic keratoses are non-cancerous growths of the outer layer of skin. There may be just one growth or clusters. They are usually brown but can vary in color from light tan all the way to black. They’re different sizes as well – anywhere 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 or stuck-on look. They sometimes look like a dab of warm, brown candle wax that has dropped onto the skin.
What causes them?
Almost everybody will eventually develop at least a few of these growths. They are sometimes referred to as “barnacles of old age.” These become more common and more numerous with advancing age. Some people develop only a few. Sometimes seborrheic keratoses may erupt during pregnancy, following estrogen therapy or in association with other medical problems.
Where do they appear?
Seborrheic keratoses are most often found on the chest or back. They’re also found on the scalp, face, or neck or almost anywhere on the body. They’re less common below the waist. Since they are not caused by sunlight they can be found on sun-exposed or covered areas. When they first appear, the growths usually begin one at a time as small, rough bumps. Eventually, they thicken and develop a rough, warty surface.
Can anyone get seborrheic keratoses?
Although seborrheic keratoses may first appear in one spot and seem to spread to another, they are not catching. As people age, they may simply develop a few more.
How serious are they?
Everybody gets at least a few of these growths. Unless they develop suddenly, they do not indicate a serious health problem. They’re not related to skin cancer. They may be unsightly, especially if they begin to appear on the face. They can get irritated by clothing rubbing against them. Because they may grow larger over the years, removal is sometimes recommended especially if they get irritated and bleed easily. A seborrheic keratosis may turn black and may be difficult to distinguish from a skin cancer. Sometimes such a growth may be removed and studied under a microscope to determine if it is cancerous or not.
Can they be prevented?
Salves, ointments, or medications can neither cure nor prevent seborrheic keratoses.