Seborrheic Keratosis

Topic Overview

What are seborrheic keratoses?

Seborrheic keratoses are noncancerous (benign) skin growths that some people develop as they age. They often appear on the back or chest, but can occur on any part of the body. Seborrheic keratoses grow slowly, in groups or singly. Most people will develop at least one seborrheic keratosis during their lifetime.¹

How can I identify a seborrheic keratosis?

The appearance of seborrheic keratoses can vary widely. They may be light tan to brown or black. The most common texture is rough, with a bumpy, grainy surface that crumbles easily.² However, they also may be smooth and waxy. They usually look like they've been stuck onto the skin. While some are tiny, 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?

We don't know what causes seborrheic keratoses, although the tendency to develop them may be inherited.¹ It is possible that they are related to sun exposure.¹ They are not contagious, so you cannot give them to someone else. There is no known way to prevent them.

Seborrheic keratoses primarily affect people older than 30.¹ Some women notice that they develop them during pregnancy or after taking estrogen. They are increasingly common in the later decades of life. Children seldom develop these skin growths.

Are there risks related to seborrheic keratoses?

A diagnosed seborrheic keratosis is nothing to worry about. However, 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. However, if a seborrheic keratosis is easily irritated or painful or its appearance 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 health professional 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:	Shannon Erstad, MBA/MPH	Last Updated: March 16, 2007
Medical Review:	Kathleen Romito, MD - Family Medicine Randall D. Burr, MD - Dermatology
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