Seborrheic Keratoses

What are seborrheic keratoses?

Seborrheic Keratoses (SKs) are common, harmless (benign) skin lesions.  They begin to develop in the 30s and 40s and by age 60, almost 90% of people have SKs.  SKs are not precancerous, but skin cancer can develop in a seborrheic keratosis, and sometimes they can be confused with skin cancer. Most SKs are removed for cosmetic reasons, or because they are itching, bleeding, increasing in size or catching on jewelry and clothing.

SKs are usually raised, small brown, black or tan, grey, yellow or mixed colored lesions. They typically look scaly, warty or greasy but can appear smooth and waxy. A characteristic of an SK is that it looks as though it is pasted or stuck on the skin. SKs often develop in groups on the skin of the face, scalp, chest, neck, stomach and back. When irritated an SK can become inflamed, red and crusty. They may itch and picking at them can cause them to bleed and potentially become infected.

What causes seborrheic keratoses?

The cause is not known but sunlight is a common risk factor. Other risk factors include having fair skin and a family history of SKs. People of color can also develop SKs, but in dark skin SKs tend to develop around the eyes and on the cheeks.  SKs often develop in skin folds where the skin rubs together, for example the groin or under the breasts.

How are seborrheic keratoses diagnosed?

SKs have a characteristic appearance and can be diagnosed by that appearance. If there is a suspicion that the growth may be problematic, Dr. Higgins will take a shave biopsy and send it to a lab to confirm the diagnosis.

What is the treatment for seborrheic keratoses?

The shave biopsy often removes an SK. When a biopsy is unnecessary an SK can be removed if it becomes irritated, bleeds, itches or catches on clothing or jewelry.

SKs can also be removed by cryosurgery using liquid nitrogen to freeze the lesion. After a few days the lesion will dry up and fall off. SKs can also be removed with curettage and electrodessication using a high frequency electric current to destroy the cells.  Once removed, an SK will not grow back, but new ones can develop.

If any of your SKs change in color or appearance call for an appointment so they can be evaluated by Dr. Heather Higgins.