Seborrheic Keratosis

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is seborrheic keratosis?

Seborrheic keratosis is a dark, scaly or wart-like skin growth that commonly develops in older people. People may confuse these growths with more serious skin conditions, such as melanoma, but seborrheic keratoses are not cancerous. They are not related to any kind of infection nor are they contagious.

Anyone can get seborrheic keratoses, though they are rare in young people and very common in people over age 50. People are more likely to get these growths if seborrheic keratosis runs in their family.

Seborrheic keratoses typically take time to develop, but many may grow at the same time, typically on the face, chest, shoulders or back. They usually appear as tan or brown, but they can also be white or black. These growths can be very small but sometimes they grow larger than an inch in diameter. Many people report that the growths become itchy or painful if they rub on clothing.

While the growths may be annoying, seborrheic keratosis treatment is not necessary unless they become bothersome or you don’t like the appearance. In that case, a dermatologist can remove them for you.

What are the symptoms of seborrheic keratosis?

A seborrheic keratosis is a well-defined round or oval-shaped growth on the skin, typically raised with a waxy or scaly appearance. This growth may look similar to a wart, with a look of being “stuck on” the skin. Seborrheic keratoses are often brown, black, tan or white, and they can be very small or more than an inch across. They tend to show up on the face, chest, arms, shoulders or back, and there are usually several of them in a given area.

Many people have no symptoms from seborrheic keratoses, while other people say the growths itch or become irritated when clothing rubs against them. In some cases, the growths may bleed due to friction.

Seborrheic keratoses typically enlarge slowly over time and develop an external surface with many clefts and crevices. While seborrheic keratoses are not cancerous or infectious, be sure to talk with your doctor if you notice a bunch of the growths develop suddenly at the same time. Many showing up at once could be a sign of internal cancer, such as colon or lung cancer, which requires treatment.

What does seborrheic keratosis look like?

Seborrheic keratoses are round- or oval-shaped growths on the skin, typically darker than the person’s normal skin tone and slightly raised. Here is a photograph of a seborrheic keratoses on a person’s back:

skin tags or seborrheic keratosis on man's back
Getty

A magnified view of the growth:

magnified-seborrheic-keratosis.jpg
Getty

What causes seborrheic keratosis?

Exact seborrheic keratosis causes are still unknown. They may be related to sun exposure. Genetics may also play a role, since seborrheic keratosis tends to run in families. And because they tend to occur more often and in greater numbers in people older than 50, it could be related to normal skin aging.

What are the risk factors for seborrheic keratosis?

Anyone of any age can develop seborrheic keratosis, but some people have a higher chance of developing it. Risk factors for seborrheic keratosis include:

  • Older age, typically over age 50

  • Family history of seborrheic keratosis

  • Lighter skin tone

What are some conditions related to seborrheic keratosis?

Seborrheic keratosis is not cancer, but the patches often resemble the signs of two more serious conditions: actinic keratosis and melanoma. Melanoma is an invasive skin cancer, while actinic keratosis has the potential to lead to skin cancer if not treated. Seborrheic keratosis treatment is not necessary, but melanoma and actinic keratosis need medical attention.

Differences between seborrheic keratosis and melanoma

Seborrheic keratosis can be mistaken for melanoma, as both appear as dark growths on the body. However, unlike seborrheic keratosis, signs of melanoma include:

  • A smooth surface

  • Ragged or blurry edges

  • Asymmetrical

  • More than one color

  • Dilated blood vessels surrounding it

  • Grows and changes rapidly

Differences between seborrheic keratosis and actinic keratosis 

Similarly, people may confuse seborrheic keratosis with actinic keratosis, with its scaly patches on the body. But the telltale patches of actinic keratosis look different in a few ways, including:

  • Lighter color, such as pink or red

  • Completely or mostly flat

  • Feels rough rather than wart-like

  • Typically show up on skin frequently exposed to the sun

Because these conditions have a similar appearance and some of the same characteristics, it can be difficult to know what is dangerous and what is benign. It is best to have a dermatologist look at the patches to get an accurate diagnosis and treatment if needed.

How do doctors diagnose seborrheic keratosis?

Most of the time, a dermatologist can diagnose seborrheic keratosis by looking at the growth. In some cases, the dermatologist may use a handheld microscope for a closer look.

The dermatologist may ask if you have noticed any changes in the appearance of the growth. If your dermatologist suspects the growth may be cancer or precancer rather than seborrheic keratosis, they may take a biopsy for a lab analysis.

What are the treatments for seborrheic keratosis?

Seborrheic keratosis is a benign condition that does not require treatment. However, some people are bothered by irritation from friction or by the appearance of these dark, raised growths. In that case, you may want to remove it. Your dermatologist will numb the treatment area and use one of these methods to remove the growth:

  • Freezing: This procedure is called cryotherapy and uses liquid nitrogen to freeze the growth, which will later fall off. 

  • Burning: In a minor surgical procedure called electrodessication, your dermatologist uses electricity to burn the growth. Your doctor may choose this removal method in combination with curettage, in which the doctor scrapes the growth away. 

  • Shaving: The doctor shaves the growth and sends a sample of it for lab examination.

  • Laser removal: The dermatologist can use a laser to burn and remove the growth. 

  • Prescription-strength hydrogen peroxide: This treatment is performed in a dermatologist’s office with a very strong solution of hydrogen peroxide. More than one treatment with the solution may be necessary. 

There are also some seborrheic keratosis treatment methods that you can use at home with over-the-counter products. They are less effective than professional seborrheic keratosis removal, but they don’t leave a wound to care for. Some of these options include:

  • Tazarotene cream 0.1%

  • Salicylic acid peels and other products with alpha-hydroxy acid

  • Vitamin D3 cream

After a diagnosis from your dermatologist that the growths are in fact seborrheic keratosis and not a more serious condition, you can discuss with the doctor which treatment would be best for you. Do not try to scrape away any growths on your own, as you could develop an infection and leave a scar.

What are the potential complications of seborrheic keratosis?

Someone with seborrheic keratosis typically does not run the risk of complications from the condition itself. However, a doctor should always examine a new growth to confirm that it is seborrheic keratosis and not a more serious condition.

A secondary infection can develop if a person attempts to scrape or pick off a growth at home. If a growth becomes bothersome or you dislike the appearance, it is best to leave the removal to a dermatologist.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Dec 12
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