Seborrheic Keratosis

Although Seborrheic Keratosis (seb-o-REE-ick Ker-ah-TOE-sis) is often confused with warts, they are quite different.

Seborrheic keratoses (SKs) 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. They vary in size from a fraction of an inch in diameter to larger than a half-dollar. A main feature of SKs 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.



Actinic Keratosis

Eczema/Atopic Dermatitis

Herpes Zoster



Seborrheic Keratosis

Skin Cancer


We do not know the exact cause of SKs. However, 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 many over time, while others develop only a few. Sometimes SKs may erupt during pregnancy, following estrogen therapy, or in association with other medical problems.


SKs are most often found on the chest or back, although, they can also be found on the scalp, face, neck, or almost anywhere on the body. They appear less often 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, itchy bumps. Eventually, they thicken and develop a rough, warty surface.


Children rarely develop seborrheic keratoses. Although SKs may first appear in one spot and seem to spread to another, they are not contagious. As people age they may simply develop a few more.


Almost everybody gets at least a few of these growths. Unless they develop suddenly, SKs do not indicate a serious health problem, and is 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 itch, get irritated, or bleed easily. An SK may turn black and may be difficult to distinguish from skin cancer. Sometimes such a growth must be removed and studied under a microscope to determine if it is cancerous or not.


Salves, ointments, and medications can neither cure nor prevent SKs.


Although these growths are frequently confused with warts, moles, actinic keratoses (AKs), and melanoma skin cancer, they differ in a variety of ways.

  • Warts are caused by a virus; SKs aren’t caused by a virus. Warts tend to develop more quickly, they don’t get as dark in color, and they don’t have that “pasted-on” appearance.
  • Moles are skin-colored, or tan to brown in color. Almost everyone develops 20-30 moles during his or her lifetime-usually during childhood.
  • Actinic keratoses (AKs), sometimes referred to as solar keratosis, are caused by the sun, and occur on body areas that have been exposed to the sunlight. The face, hands, forearms, and V of the neck are the most common areas for AKs. These growths are more common among pale-skinned, fair-haired, light-eyed individuals. They are flatter, redder, and rougher than SKs. AKs are pre-cancerous, which means they may become skin cancers. Any raised, reddish, rough-textured growth should be examined by a dermatologist.
  • Melanoma is a serious form of skin cancer. Melanomas are often, but not always, dark brown to bluish-black growths. Melanomas may be confused with SKs because both can become very dark. It is wise to have any growth that turns dark, bleeds, itches, or becomes irritated checked by a dermatologist. Early detection of skin cancer is the best way to assure successful treatment.