Overview
A seborrheic keratosis (seb-o-REE-ik ker-uh-TOE-sis) is a common noncancerous (benign) skin growth. People tend to get more of them as they get older.
Seborrheic keratoses are usually brown, black or light tan. The growths (lesions) look waxy or scaly and slightly raised. They appear gradually, usually on the face, neck, chest or back.
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, more than 1 inch (2.5 centimeters) across.
Seborrheic keratoses are harmless and not contagious. They don't need treatment, but you may decide to have them removed if they become irritated by clothing or you don't like how they look.
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 grows gradually. Signs and symptoms might include:
- A round or oval-shaped waxy or rough bump, typically on the face, chest, a shoulder or the back
- A flat growth or a slightly raised bump with a scaly surface, with a characteristic "pasted on" look
- Varied size, from very small to more than 1 inch (2.5 centimeters) across
- Varied number, ranging from a single growth to multiple growths
- Very small growths clustered around the eyes or elsewhere on the face, sometimes called flesh moles or dermatosis papulosa nigra, common on Black or brown skin
- Varied in color, ranging from light tan to brown or black
- Itchiness
When to see a doctor
See your doctor if the appearance of the growth bothers you or if it gets irritated or bleeds when your clothing rubs against it. Also see your doctor if 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
Experts don't completely understand what causes a seborrheic keratosis. This type of skin growth does tend to run in families, so there is likely an inherited tendency. If you've had one seborrheic keratosis, you're at risk of developing others.
A seborrheic keratosis isn't contagious or cancerous.
Risk factors
The peak time for developing seborrheic keratoses is after your 50s. You're also more likely to have them if you have a family history of the condition.
