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.
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.
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.