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Seborrheic keratoses are common benign (noncancerous) skin growths that can occur anywhere on the body. While it is possible to have a seborrheic keratosis, it is more common to develop many of these growths, especially with increased age.
WHAT DOES AN SK LOOK LIKE?
Most SKs begin as small, rough bumps on the skin, though some can be smooth and flat. These bumps tend to grow
slowly and thicken gradually.
SKs are often brown, although they may range in color from light tan to black. They can vary in size from as small as a
fraction of an inch to larger than an inch.
SKs usually have a waxy, stuck-on-the-skin appearance, like a dab of warm candle wax. While this may make an SK look like it can be removed easily with a fingernail, you should not try this, as it could lead to irritation, a skin infection or a scar, and the SK will grow back.
SKs may look like other common skin growths, including:
- Warts: Although warts are generally harmless, they are caused by a virus and can spread. A dermatologist may recommend treatment, especially if you cannot get rid of a wart with treatment at home, a wart hurts or you have many
- Actinic keratoses: These dry, scaly growths are flatter and rougher than SKs. AKs are caused by years of unprotected exposure to ultraviolet radiation from the sun or indoor tanning beds. They are considered precancerous, as they may turn into a type of skin cancer called squamous cell carcinoma if they are left untreated.
- Moles: While it is normal for new moles to develop during childhood and adolescence, new moles usually do not appear in adults. A new mole may be a sign of melanoma, the deadliest form of skin
- Melanoma: Melanoma can look like an SK, as both can grow quickly and become dark and irregular in shape. While melanoma can be deadly, it is highly treatable when detected
While SKs are harmless, other growths that may be dangerous could be mistaken for an SK. If you notice any new or
suspicious spots on your skin, or anything changing, itching or bleeding, see a board-certified dermatologist.
WHERE DO SKS APPEAR ON THE BODY?
SKs can form anywhere on the skin, except the palms of the hands and the soles of the feet. Most SKs appear on the chest, back, scalp, face and neck.
WHO GETS SKS?
While anyone may develop SKs, these growths generally appear in middle age or later. Children rarely develop SKs.
While SKs are more common in people with fair skin, they also can develop in people with darker skin tones. In people with skin of color, SKs tend to be small and appear around the eyes and on the cheeks.
WHAT CAUSES SKS?
The exact cause of SKs is unknown. The number of growths a person has tends to increase with age. While this may
make it appear like the growths are spreading, this is not the case, as SKs are not contagious.
SKs tend to run in families. They also may suddenly appear when a woman’s estrogen levels quickly rise or fall, such
as during pregnancy or after estrogen therapy.
SKs can form on both skin that gets sun exposure and skin that gets little or no sun. Therefore, more research is
needed to determine if UV light exposure plays a role in causing SKs.
SHOULD I SEE A DERMATOLOGIST ABOUT MY SKS?
SKs are benign, so treatment is generally not necessary. SKs are rarely a sign of a serious health problem.
However, you should see a board-certified dermatologist if you have any new or suspicious growths on your skin, as well as any growths that are changing, itching or bleeding, as these could be signs of skin cancer. Your dermatologist will examine the growth and may perform a biopsy, which involves removing all or some of the growth and sending it to a lab for evaluation.
HOW DO BOARD-CERTIFIED DERMATOLOGISTS TREAT SKS?
Some patients ask their dermatologist to remove SKs that are large, irritated by clothing or jewelry, or considered unsightly. Check with your insurance company before asking your dermatologist to remove an SK, as this may be considered an elective cosmetic procedure that is not covered by your carrier.
A board-certified dermatologist will decide the most appropriate treatment for your SK. In-office procedures to
remove an SK include:
- Cryotherapy: The dermatologist uses liquid nitrogen to freeze the SK, causing it to fall off within days. Sometimes a blister forms beneath the treated SK and dries into a scab-like crust, which eventually falls off as
- Electrosurgery and/or curettage: The dermatologist may use an electric current to destroy the SK and/or a scoop-shaped instrument, called a curette, to scrape off the treated growth. Some patients may require only one of these steps. Stitches are not
- Topical treatment: The dermatologist applies a hydrogen peroxide solution to raised SKs to remove them over the course of two office visits. While the risk of scarring is low, side effects may include itching, stinging, crusting, swelling, redness and scaling at the application
- Laser treatments: Different types of laser treatments are available to treat SKs. These treatments are helpful when treating a large number of SKs, difficult-to-eliminate SKs and thicker SKs. Although there is less scarring associated with this kind of treatment, there is an increased risk of permanent loss of skin color in the
Multiple seborrheic keratoses
After SK treatment, you may see a small red, dark or light spot on your skin where the growth used to be. While this usually fades with time, a permanent light or white spot is a possible side effect of SK treatment, especially if you have a darker complexion.
A board-certified dermatologist is a medical doctor who specializes in the diagnosis and medical, surgical and cosmetic treatment of skin, hair and nail conditions. To learn more about seborrheic keratoses or to find a board-certified dermatologist in your area, visit aad.org/SKs or call toll-free (888) 462-DERM (3376).
All content solely developed by the American Academy of Dermatology.
Copyright © by the American Academy of Dermatology and the American Academy of Dermatology Association.
Images used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides
American Academy of Dermatology
P.O. Box 1968, Des Plaines, Illinois 60017
AAD Public Information Center: 888.462.DERM (3376) AAD Member Resource Center: 866.503.SKIN (7546) Outside the United States: 847.240.1280
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