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Seborrheic keratosis

Overview

Seborrheic keratosis (seb-o-REE-ik ker-uh-TOE-sis) is one of the most common noncancerous skin growths in older adults.

A seborrheic keratosis usually appears as a brown, black or light tan growth on the face, chest, shoulders or back. The growth has a waxy, scaly, slightly elevated appearance. Seborrheic keratoses don't become cancerous and aren't thought to be related to sun exposure, but they can look like skin cancer.

Seborrheic keratoses are normally painless and require no treatment. You may decide to have them removed if they become irritated by clothing or for cosmetic reasons.

Seborrheic keratoses on the back

Seborrheic keratoses are very common on the back. They appear as waxy light tan, brown or black growths that look as if they were dripped onto the skin by a candle. Some can grow large, up to 1 inch (2.5 centimeters) across.

Seborrheic keratoses on the back

Seborrheic keratoses are very common on the back. They appear as waxy light tan, brown or black growths that look as if they were dripped onto the skin by a candle. Some can grow large, up to 1 inch (2.5 centimeters) across.

Close-up of seborrheic keratoses

Seborrheic keratoses are usually round or oval and range in color from light tan to black. They can develop as a single growth or in clusters.

Symptoms

A seborrheic keratosis usually looks like a waxy or wart-like growth. It typically appears on the face, chest, shoulders or back of the body. You may develop a single growth or cluster of them. A seborrheic keratosis:

  • Varies in color, usually from light tan to brown or black
  • Is round or oval shaped
  • Has a characteristic "pasted on" look
  • Is flat or slightly elevated with a scaly surface
  • Ranges in size from very small to more than 1 inch (2.5 centimeters) across
  • May itch

Seborrheic keratoses aren't usually painful, but they can be bothersome depending on their size and location. Be careful not to rub, scratch or pick at them. This can lead to bleeding, swelling and, in rare cases, infection.

When to see a doctor

See your doctor if:

  • Many growths develop over a short time.
  • The growths get irritated or bleed when your clothing rubs against them. You may want the growths removed.
  • You notice suspicious changes in your skin, such as sores or growths that grow rapidly, bleed and don't heal. These could be signs of skin cancer.

Causes

The exact cause of seborrheic keratoses isn't known. They are very common and generally increase in number with age. The lesions aren't contagious. They tend to run in some families, so inheritance may play a role.

Risk factors

You can develop seborrheic keratoses at any age, but you're generally more likely to develop them if you're over age 50. You're also more likely to have them if you have a family history of the condition.

Diagnosis

Your doctor can usually diagnose seborrheic keratosis by inspecting the growth. He or she might recommend removing the tissue so it can be examined under a microscope.

Treatment

Treatment of seborrheic keratoses usually isn't necessary. You may want them removed if they become irritated, if they bleed because your clothing rubs against them, or if you simply don't like how they look or feel.

Your doctor can remove seborrheic keratoses using several methods, including:

  • Freezing with liquid nitrogen (cryosurgery). Cryosurgery can be an effective way to remove seborrheic keratoses. It doesn't always work on raised growths, and it may lighten treated skin.
  • Scraping the skin's surface with a special instrument (curettage). Sometimes curettage is used along with cryosurgery to treat thinner or flat growths. It may be used with electrocautery.
  • Burning with an electric current (electrocautery). Electrocautery can be effective in removing seborrheic keratoses. It can be used alone or with curettage. This procedure can leave scars if it's not done properly, and it may take longer than other removal methods.
  • Vaporizing the growth with a laser (ablation). Different types of laser treatments are available to treat seborrheic keratoses.

Preparing for an appointment

You're likely to start by first seeing your primary care doctor. In some cases when you call to set up an appointment, you may be referred directly to a specialist in skin diseases (dermatologist).

Because appointments can be brief, it's a good idea to be well-prepared for your appointment. Here's some information to help you get ready for your appointment.

What you can do

For seborrheic keratosis, some basic questions to ask your doctor include:

  • Are tests needed to confirm the diagnosis?
  • What is the best course of action?
  • Will the lesions go away on their own?
  • What suspicious changes in my skin should I look for?

Don't hesitate to ask other questions that come up during your appointment.

What to expect from your doctor

Your doctor may ask:

  • When did you first notice the skin lesions?
  • Have you noticed multiple growths?
  • Have you noticed any changes in the growth?
  • Is the condition bothersome?
  • Do any family members also have this condition?

Last updated: October 13th, 2016

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