Definition

Seborrheic keratosis is a type of benign (noncancerous) raised growth on the skin. Seborrheic means greasy (often the growth is not greasy). Keratosis means thickening of skin. The growths develop from the top layer of skin. These growths may look like warts. But, they do not extend deep into the skin or contain the viruses that cause warts.

Seborrheic keratoses are not contagious, do not spread, and do not turn into cancerous tumors. They do not threaten your health. But, they can be irritating or cosmetically displeasing.

Skin Section with Seborrheic Keratosis

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Causes

The direct cause of seborrheic keratoses is unknown.

Risk Factors

Risk factors include:

• Age: over 40
• Having close family members with the condition

Symptoms

Seborrheic keratosis:

• Can be located anywhere on body, but usually appear on the chest, torso, face, shoulders, or back
• Are typically yellow, tan, brown, or black
• Are raised
• May have a rough or wart-like texture
• May have a pasted look, as if dirt or clay is stuck on the skin
• Usually have a round or oval shape
• Can be one or more than one growths
• May be itchy
• Can be irritated by clothing or jewelry and can bleed if picked or rubbed

Diagnosis

Some seborrheic keratoses appear dark. It may be difficult to tell them apart from pigmented growths that are prone to becoming cancerous. It is important that you have a doctor check and make sure they are seborrheic keratoses. Doctors can usually make an accurate diagnosis upon examination of the skin growth. A biopsy can be done to make sure in uncertain cases.

Treatment

Talk with your doctor about the best treatment plan for you. Seborrheic keratoses do not pose a threat to your health. The best course of action may be to leave them alone. If they itch or become irritated, or if you feel they affect your appearance, they can be removed.

Treatment options include:

Prevention

There are no steps to prevent seborrheic keratosis because the cause is not clear.