What Is Seborrheic Keratosis?

A seborrheic keratosis is usually easily identified by appearance.

Texture

Growths often start as small, rough areas. Over time, they tend to develop a thick, wart-like surface. They may have a “stuck-on” appearance, look waxy, and have slightly raised surfaces.

Shape

Growths are usually round or oval-shaped.

Color

Growths can range in color from white to black but are frequently tan or brown.

Location

Multiple lesions may appear, although there might be just one at the beginning. Growths can occur anywhere on the body except the soles of the feet, palms, and mucous membranes. Some places they may show up include the:

• scalp
• face
• chest
• shoulders
• abdomen
• back

Seborrheic keratosis vs. actinic keratosis

Actinic keratosis, another type of skin growth, isn‘t the same as seborrheic keratosis. An actinic keratosis is a rough skin patch that usually develops in areas of the skin that receive a lot of sun exposure. Unlike a seborrheic keratosis, it‘s considered precancerous.

An actinic keratosis is also called a solar keratosis.

While seborrheic keratosis is not harmful and does not usually need treatment, it can look similar to melanoma, a serious type of skin cancer.

If your skin changes unexpectedly, you should always have it looked at by a doctor or dermatologist.

Seborrheic keratosis doesn’t need treatment. However, a healthcare professional such as a dermatologist may decide to remove growths if they have a suspicious appearance or cause physical or emotional discomfort.

Treatment and removal methods for seborrheic keratosis can include the following:

• Cryosurgery: Cryosurgery uses liquid nitrogen to freeze off the growth.
• Electrosurgery: In electrosurgery, a healthcare professional uses an electrical current to scrape off the growth. A healthcare professional numbs the area before the procedure.
• Curettage: In curettage, a healthcare professional scrapes off the growth with a curette, a scoop-like surgical instrument. Curettage is sometimes combined with electrosurgery.
• Shave excision: Shave excision is similar to curettage. A healthcare professional may perform it if they want to send a sample of the growth to a lab for analysis.
• Ablation: This procedure uses a special laser to vaporize the growth.
• Hydrogen peroxide solution: The Food and Drug Administration (FDA) approved a 40% hydrogen peroxide solution (Eskata) to destroy seborrheic keratosis cells. It’s only available by prescription. However, this method often causes skin irritation, according to a 2019 report.
• Nitric acid-zinc solution: The topical solution Nitrizinc Complex contains nitric acids, zinc, copper salts, and organic acids. A small 2019 study found this method to be safe and effective at shrinking or eliminating most lesions within a 6-month period.

After having seborrheic keratosis professionally removed, your skin may be lighter at the site of removal. The difference in skin color often becomes less noticeable over time.

Most of the time a seborrheic keratosis growth won’t return, but it’s possible to develop a new one on another part of your body.

Is it okay to scratch off seborrheic keratosis?

Dermatologists recommend not removing skin growths yourself.

Attempting to remove seborrheic keratosis by picking or scratching at it can result in complications, such as:

• bleeding
• inflammation
• infection

Because doctors typically submit growths removed from your skin to a lab for testing, removing a growth yourself can potentially also delay a skin cancer diagnosis.

Experts don’t know what causes seborrheic keratosis to develop. They aren‘t bacterial, viral, or contagious.

The following risk factors may make you more likely to develop a seborrheic keratosis:

• Older age: The condition often develops in middle age.
• Having family members with seborrheic keratosis: This skin condition appears to run in families and can often be inherited. The risk increases with the number of affected biological relatives.
• Pregnancy or hormone therapy: Seborrheic keratoses may develop during pregnancy. These growths may also develop while a person undergoes estrogen replacement therapy.
• Frequent sun exposure: Some subtypes of seborrheic keratosis may occur more often in sun-exposed skin than protected skin. However, seborrheic keratoses can also appear on skin that you usually cover up when outdoors.
• Having lighter skin: Seborrheic keratoses are generally more common in people with light skin, although people with darker skin can develop them too. Some experts believe that dermatosis papulosa nigra, a skin condition that’s more common in people with darker skin, may be a subtype of seborrheic keratosis.

A dermatologist can often diagnose seborrheic keratosis by sight. If there’s any uncertainty, they’ll likely remove part or all of the growth for testing in a laboratory. This is called a skin biopsy.

A trained pathologist then examines the biopsy sample under a microscope. This step can help a doctor or dermatologist diagnose the growth as either seborrheic keratosis or something else.

A seborrheic keratosis isn’t dangerous, but it can be difficult to distinguish between harmless and dangerous growths. Something that looks like seborrheic keratosis could actually be melanoma.

Have a healthcare professional check your skin if:

• There’s a new growth.
• There’s a change in the appearance of an existing growth.
• There’s only one growth (seborrheic keratosis usually appears as several growths).
• A growth has an unusual color, such as purple, blue, or reddish-black.
• A growth has borders that are blurred, jagged, or otherwise irregular.
• A growth is irritated or painful.

If you’re worried about any growth, make an appointment with a doctor or dermatologist. It’s better to be too cautious than ignore a potentially serious problem.