Seborrheic Keratosis

Topic Overview

What are seborrheic keratoses?

Seborrheic keratoses (say "seh-buh-REE-ick kair-uh-TOH-seez") are skin growths that some people get as they age. They are benign, which means they are not a type of cancer. The way they look may bother you, but they aren't harmful.¹

These skin growths often appear on the back or chest, but they can occur on any part of the body. They grow slowly, and they may appear as single growths or in groups.

Seborrheic keratoses don't spread from person to person. There is no known way to prevent them.

These skin growths are common in middle-aged people, but they can appear as early as the teen years.² Some women get them during pregnancy or after taking estrogen. Children seldom have them.

What causes seborrheic keratoses?

Experts don't know what causes seborrheic keratoses. But research has found that:²

• They tend to run in families.
• They seem to be related to sun exposure.

What are the symptoms?

Seborrheic keratoses usually cause no symptoms. But they can itch, bleed easily, or become red and irritated when clothing rubs them.

How seborrheic keratoses look can vary widely. They:

• Range in color from white to light tan to black. Most are brown. Some are multicolored.
• Range in size from tiny to larger than about 1 in (2.5 cm) in diameter.
• Range in texture from waxy and smooth to velvety to dry, rough, and bumpy.

They also:

• May have dry scale, which you can easily pick off, or have a surface that crumbles when picked.
• Can be dome-shaped with tiny white or black "horns" growing from the surface.
• Can occur as a cluster of growths.
• Can look like skin tags (small, soft pieces of skin that stick out on a thin stem).
• Can swell and turn red.
• Slowly grow over time and seldom go away on their own.

These growths may be mistaken for warts, moles, skin tags, or skin cancer.

How are seborrheic keratoses diagnosed?

Your doctor will look at the skin growth. He or she may need to take a sample (biopsy) of the growth to rule out cancer if the growth:

• Itches or bleeds.
• Becomes inflamed and red.
• Is dark brown to black.

How are they treated?

Seborrheic keratoses don't need to be treated. But if one bothers you or you don't like how it looks, your doctor can remove it. Your doctor may freeze it off, cut it out, or use a tool that burns it off.

Since these growths aren't harmful and don't have to be treated, your insurance company may not pay for having them removed.

Should you worry about seborrheic keratoses?

A diagnosed seborrheic keratosis is nothing to worry about. But if you are unsure what type of skin growth you have, see your doctor. It may be hard to tell whether the growth is a keratosis, a mole, a wart, or skin cancer.

If you have a dark skin growth or any growths that form quickly, call your doctor right away.

Frequently Asked Questions

Learning about seborrheic keratosis:	What is a seborrheic keratosis? What does it look like? What skin growths look similar to seborrheic keratoses?
Being diagnosed:	How does my doctor diagnose a seborrheic keratosis?
Getting treatment:	How is a seborrheic keratosis treated? How do I care for it at home?

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Author:	Bets Davis, MFA	Last Updated: February 26, 2009
Medical Review:	Kathleen Romito, MD - Family Medicine Alexander H. Murray, MD, FRCPC - Dermatology
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