What Is Seborrheic Keratosis?

Medically Reviewed by Zilpah Sheikh, MD on April 18, 2024
Written by Tammy Worth
7 min read

Seborrheic keratosis is a common, harmless growth on your skin. It's benign, which means it isn't cancerous. Like moles, seborrheic keratosis happens when extra skin cells bunch up together on the top layer of skin. It can appear later in life, after about age 40. It can show up anywhere except your palms and soles. It’s most likely to happen on your face, scalp, chest, shoulders, belly, or back.

Often, your doctor can identify seborrheic keratosis just by looking at it. If your doctor isn’t sure, they’ll do a biopsy to remove the growth and study it more closely.

 

Normally, it has a round or oval shape. It ranges from light tan to black in color. You may first notice that it looks and feels soft and smooth, like velvet, and can be very small.

Over time, seborrheic keratoses become scaly and thick, like melted candle wax stuck to your skin. They can grow to about 1 inch in width. You may have one spot, or they can grow in groups. Some people have hundreds on their bodies. When they grow in clusters on your face or around your eyes, they are known as dermatosis papulosa nigra. This is more common if your skin is black or brown.

It’s not painful, but it might itch. It can feel greasy, rough, or soft when you touch it. Inflamed seborrheic keratoses can rub against your clothes and get in the way of shaving and other things you do. Even though it can be annoying, it’s important not to scratch, pick, or rub the area. That can cause it to swell, bleed, or get infected.

Seborrheic keratosis isn't cancerous, so it's important to be able to distinguish it from similar skin conditions such as melanoma and actinic keratosis.

Melanoma and seborrheic keratosis are both similar to moles, typically brown or black in color, and can appear anywhere on your body. But melanoma is more likely to:

  • Show up as one spot, not in clusters or different areas
  • Be smooth
  • Have a ragged border
  • Be different colors
  • Be asymmetrical
  • Grow quickly

Actinic keratosis is also similar to seborrheic keratosis but can (about 5%-10% of the time) turn into skin cancer. Both conditions usually appear after age 40 and look crusty. Actinic keratosis often turns bumpy over time and can itch and bleed if inflamed. If a spot is actinic keratosis, it is more likely to:

  • Be lighter than seborrheic keratosis
  • Be flatter than seborrheic keratosis
  • Be felt before you see it
  • Show up in clusters on areas of skin that get a lot of sun exposure

If you're not sure what skin condition you might have, talk to your doctor so they can rule out anything that might be cancerous.

Doctors aren’t sure what causes seborrheic keratosis. So, there’s no real way to prevent it. But some things may put you at a higher risk, such as:

Genes. The condition tends to run in families. You're more likely to have one if other people in your family have it too.

Age. It almost always happens later in life, especially after age 50. And about 90% of people older than 65 have at least one seborrheic keratosis.

Skin tone. It's most common in people with light skin.

Hormones. Changes in estrogen levels may be a factor that causes it, so it can appear during pregnancy, or if you’ve had hormone replacement therapy.

Sun exposure. Some studies show sunlight might play a part, but the growths can show up with or without exposure to the sun.

Genetics. You are more likely to have it if you have some genetic mutations, includingPIK3CA.

Also, if you've had seborrheic keratosis, you are more likely to have another one.

Is seborrheic keratosis contagious?

It's not contagious. If you have one, it won’t spread to other people or other parts of your body, but it is common to have not just one, but many.

Most of the time, seborrheic keratosis won’t cause problems. But make an appointment if:

  • It bothers you a lot or becomes irritated or inflamed
  • You notice lots of growths at once — normally, they appear one or two at a time and increase in number
  • It seems to change or grow quickly
  • It bleeds and doesn’t heal
  • You suddenly have many growths, because it can be what's known as a Leser-Trélat sign, which can signal different types of cancer (though this is very rare)

If any of these things happen, or if you just don’t like how a growth looks or feels on your skin, your doctor can remove it.

When you see your doctor about seborrheic keratosis, they will perform a physical exam to look at the spot or spots. They can often tell just by looking at it whether it's seborrheic keratosis or another condition. They may ask these questions during the exam:

  • How long you've had the spot
  • If you have a family history of seborrheic keratosis or melanoma
  • How many growths you have
  • How much it bothers you
  • If you have any pain along with the spot

If your doctor isn't sure if you have seborrheic keratosis, they might use a microscope with a light to get a better view of the spot. If they are still unsure, they will probably take a small sample, or remove the spots, which will be tested in a lab.

Seborrheic keratosis treatment consists of removing the spots, which won't go away on their own. Start by talking to your regular doctor. They might refer you to a dermatologist — a skin specialist to diagnose or remove the seborrheic keratosis. If it needs to be removed, your doctor will choose one of the following simple ways to remove the growth, usually in their office or clinic. Your doctor will numb your skin before most of these treatments to make you feel more comfortable.

Burning. Electrocautery uses an electric current to burn away the seborrheic keratosis. It can take longer than other ways and can be used with other treatments, especially if your growth is very large.

Freezing. Also known as cryotherapy, this uses supercooled liquid nitrogen to freeze and remove the growth. It might require several treatments if the seborrheic keratosis is very large or thick. You may also lose pigment permanently at the spot of the growth, particularly if you have darker skin.

Laser. A harmless beam destroys the physical structure of the area.

Scraping. The doctor uses a special tool to raze it off. This is often done along with freezing or burning and is used for thinner seborrheic keratosis.

Medication. If you don't want to use one of these treatments, there is an FDA-approved medication -- 40% hydrogen peroxide solution -- that your doctor can apply in their office to remove the spot. It may take more than one treatment for it to be effective.

Most seborrheic keratoses don’t return after they’re removed. But a new one can still appear somewhere else on your body. Sometimes, removing one can make your skin a little lighter at that spot. It usually blends in better over time, but not always.

If you prefer to try an at-home treatment, there are a few that may lighten the appearance of seborrheic keratosis. None is 100% effective at making them go away, but there are few side effects. You can try:

  • Tazarotene cream, foam, or gel 0.1%
  • Products with alpha hydroxy acid such as a salicylic acid peel
  • Vitamin D3 cream

It’s normal for seborrheic keratoses to grow darker over time. But if you use an artificial tanning product that contains DHA, an omega-3 acid, it can change the color of the growths as well as the skin around them.

Some people who’ve used these products have seen seborrheic keratoses grow darker quickly. That’s because the affected skin absorbs the artificial tan pigments more than the unaffected skin. Doctors have found that this kind of color change isn’t a sign of cancer.

Seborrheic keratosis is a benign (noncancerous) condition that can look like a mole or wart. It's caused by a buildup of skin cells and can happen anywhere on your body, but often appears on the face, neck, and back. You usually have them after the age of 40. If they itch or bother you, talk to your doctor about removal.

Is it OK to scratch or scrub off seborrheic keratosis? 

No. If the spot or spots are bothering you, talk to your doctor. They can remove it for you or send you to a skin specialist for removal.Scratching or rubbing it can cause bleeding and infection.

Can seborrheic keratosis turn cancerous? 

No. Unlike some moles, seborrheic keratosis never turns cancerous. It's a benign spot.