Seborrheic Keratosis

By Kira Mayo

As we all know, many skin changes come with age. One of them is called seborrheic keratosis, also known as senile wart, senile keratosis and, very eloquently, barnacle. What are these cumbersome lesions? Why do they occur? How can you get rid of them?

Seborrheic keratoses are colored superficial skin lesions. Although the cause in unknown, they occur more frequently in sunlight-exposed areas. They usually appear in middle or old age and are most often on the neck, back, chest and abdomen. In those over 64 years, the incidence of these growths is 88%, making it the most common benign tumor in older adults.

Seborrheic keratoses vary in size and tend to grow slowly. They may be round or oval, and may be skin-colored, brown or black. They usually appear stuck onto your skin, and may have a warty, waxy, scaling or crusted surface. They can arise on any skin surface other than the palms and soles but are most commonly found on the face and trunk.

Your doctor will diagnose seborrheic keratoses based on their clinical appearance. If your doctor is unsure, a biopsy can be done to rule out a more serious diagnosis.

Some variants of seborrheic keratosis:

*Stucco keratoses present as 1-4-mm gray to white scaly bumps. These are most commonly located on the arms and lower legs.

*Dermatosis papulosa nigra is a type of seborrheic keratosis that affects up to 35% of the African American population and is characterized by multiple, firm, smooth, dark brown to black bumps that are 1-5 mm in diameter. Lesions occur mainly on the cheeks and forehead, although they also may be found on the neck, upper back, and chest. Scaling, crusting, and ulceration do not occur. Lesions usually begin during puberty and are more common among females.

*Leser-Trélat is characterized by the sudden appearance of numerous seborrheic keratoses associated with an underlying malignancy. The most common associated malignancy is an abdominal cancer.

Seborrheic keratoses are not precancerous. Therefore, there is no need to treat them unless they are irritated, itchy or cosmetically bothersome. There are various treatment options if you choose to remove them

*Cryotherapy is the most common treatment since it is quick and effective. Your doctor will use liquid nitrogen to freeze the seborrheic keratoses. Your skin tends to heal nicely with little to no scarring, but the area treated might end up having a lighter skin color.

*Electrodessiction and currettage: your doctor will numb the area with a local injection of lidocaine. The lesion is cut from the skin with a curette (a sharp, spoon-shaped tool). An electrode is then used to treat the area with an electric current that stops the bleeding and destroys cancer cells that remain around the edge of the wound. The process is repeated one to three times to remove all the cancer.

*Shave biopsies are usually done when the lesion has an atypical clinical appearance and a malignancy, such as squamous cell or basal cell carcinoma, is a possible diagnosis.

Originally written for DermHub

Cartoon via


Collison, Daniel W. “Seborrheic Keratoses: Benign Tumors.” Merck Manual Professional.

Dunwell P, Rose A. Study of the skin disease spectrum occurring in an Afro-Caribbean population. Int J Dermatol. Apr 2003;42(4):287-9.


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