Seborrheic Keratosis

Topic Overview

What are seborrheic keratoses?

Seborrheic keratoses (say "seh-buh-REE-ick kair-uh-TOH-sus") are noncancerous (benign) skin growths that some people develop as they age. They often appear on the back or chest, but they can occur on any part of the body. Seborrheic keratoses grow slowly, in groups or singly. They are usually easy for a doctor to diagnose. You may not like how they look, but they aren't harmful.¹

How can I identify a seborrheic keratosis?

How seborrheic keratoses look can vary widely. They may be pale white to brown or black. The most common texture is rough, with a bumpy, grainy surface that crumbles easily.² But they also may be smooth and waxy. They usually look like they've been stuck onto the skin. Some are tiny, and others grow larger than 3 cm (1.2 in) in diameter.²

Seborrheic keratoses may be mistaken for warts, moles, skin tags, or skin cancer.

What causes seborrheic keratoses?

Doctors don't know what causes seborrheic keratoses. But research has found:³

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

They are not contagious, so you cannot spread them to someone else. There is no known way to prevent them.

Seborrheic keratoses are common in middle-aged people, but they can appear as early as the teen years.³ Some women notice that they get them during pregnancy or after taking estrogen. Children seldom have these skin growths.

Are there risks related to seborrheic keratoses?

A diagnosed seborrheic keratosis is nothing to worry about. But seborrheic keratoses sometimes are mistaken for cancerous (malignant) skin growths. Or cancerous growths may blend in with seborrheic keratoses. If you have a skin growth that appears to be a seborrheic keratosis, ask your doctor to examine it. If you have a dark skin growth or a group of growths that develop rapidly, make an appointment to have them checked now.

How is it treated?

Seborrheic keratoses do not need to be treated. But if a seborrheic keratosis is easily irritated or painful or if the way it looks bothers you, you can have it removed.

Learning about seborrheic keratosis:	What is a seborrheic keratosis? What does a seborrheic keratosis look like? Are there risks related to seborrheic keratoses? 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 a seborrheic keratosis 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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