Seborrheic Keratosis: The Stubborn “Acne” That Isn’t Really Acne

Last Updated on January 6th, 2020

One of the most persistent of all skin problems is a particularly hard-to-treat skin condition called seborrheic keratosis. Tending to start in middle age and to stick around for the remainder of life, seborrheic keratosis takes on the appearance of acne that has been stuck onto the skin. It usually begins as one or more light brown, flat bumps on the skin. As this spot known as a macule grows, it takes on a wart-like appearance, with multiple clogged pores. The lesion grows and takes on a variety of skin tones ranging from pink to brown to dark brown to black.

Seborrheic keratoses are very rare before the age of 40, but they are very common by the age of 60. The sunnier the climate, the more likely people are to develop seborrheic keratosis. A study of 222 people in a rest home in New York found that 29% of men and 38% of women had seborrheic keratoses. A study of people 64 and older a little farther south, in North Carolina, found that 88% had at least one seborrheic keratosis, and 38% of white women, 54% of white men, and 61% of black men and women had at least 10 of these marks, usually on sun-exposed skin. And a study in Australia found that 100% of people over 50 had seborrheic keratoses, and even Australians as young as age 15 had on average 6 of these acne-like marks on the skin.

Seborrheic keratoses usually don’t cause significant problems other than getting so large that they rub against and catch on clothing. Sometimes, however, they itch. Scratching to relieve the itch can break the warty skin, and cause bleeding and infection. Groups of seborrheic keratoses can make it hard to notice skin cancer.

Most of the time the major issue with seborrheic keratosis is that it is a constant reminder of aging. Since the condition tends to appear on sun-exposed skin, the marks are most often seen on the face and hands, although they are most common on the chest and back when people spend a lot of time sunning by the pool. Because a seborrheic keratosis or a group of seborrheic keratoses involves clogged pores, it’s easy to assume the problem is due to acne, but it’s not.

Do You Have Seborrheic Keratosis?

Even teenagers can get seborrheic keratoses. Anyone who spends a lot of time in the sun can get the marks. More often than not, if you have spent a lot of time in the sun, and you have “acne” without inflammation, what you really have is seborrheic keratosis. But not every kind of acne-like mark on sun-exposed skin is seborrheic keratosis.

The marks known as lentigos, cafe au lait marks, and liver spots are flat. These are nothing more than concentrations of the skin pigment melanin where the skin has successfully defended itself against damage by the UV rays of the sun.

Basal cell carcinoma, on the other hand, has a smooth, pearl-like appearance. It’s more likely to change color from a pearly gray to an alarming red, and it may bleed even if you don’t scratch or pick at it. The more serious form of skin cancer melanoma is recognizable by four important A-B-C-D signs:

• Asymmetry. A melanoma tends to be “lop-sided,” growing more to one side than to the other.
• Borders. Melanoma tends to have ragged borders. This isn’t quite the same as having a warty, ragged exterior. Around a melanoma, it is the area where the cancerous skin meets healthy skin that will look ragged.
• Color. A melanoma can take on a distinctive, dark blue color, or turn black.
• Diameter. Malignant melanomas are usually more than 6 mm (¼ inch) in diameter.

Seborrheic keratoses can hide or mimic a melanoma, as both turn black. If you have a cluster of black marks on your skin, you really need to see a doctor for diagnosis, just in case. Melanoma is very easy to treat before it has spread, but it is very difficult to treat once it has metastasized. But there’s no need to panic, either. Here’s the rule:

• If a dark mark has a rough surface and smooth borders, it is probably non-malignant.
• If a dark mark has a smooth surface and ragged borders, and it’s more than 6 mm (¼ inch) across, it may be malignant.
• And if you have so many marks in the same place that you just can’t tell where one ends and another starts, you need to see a doctor.

Many, many more people have seborrheic keratosis than have melanoma, but it’s essential to see a doctor to know for sure.

What Can You Do About Seborrheic Keratosis?

If you know you have seborrheic keratosis, there are several things you can do. You can go to either a family doctor or a dermatologist and have the marks frozen off with cryotherapy, using liquid nitrogen or dry ice. This method allows the doctor to take a sample of the skin to make doubly sure there is no cancer. The older method of burning out the seborrheic keratosis with an electric needle does not.

Or you could make an appointment with a licensed aesthetician at a spa. The aesthetician or cosmetologist can apply trichloroacetic acid to the spot and burn it away in one treatment.

Or there is a much less expensive, slower way to get rid of seborrheic keratoses, and some of the same products that work for acne also work for seborrheic keratosis. Applying lactic acid or alpha-hydroxy acid, or both, slowly removes the tough layer of skin around the bump. After 2 or 3 months, the bump is gone—and it will be a lot easier to make sure that other, more serious skin conditions don’t exist. Skincare creams with the ingredient curcumin, applied after exposure to the sun (you don’t want to wear them in the sun when sunlight would be breaking down the active ingredient that rejuvenates your skin), keep seborrheic keratoses away for good.

If you don’t like the idea of getting your skin frozen with dry ice or liquid nitrogen, you’re not into electric needles, and you don’t care to go to a day spa to get burned with acid, try exfoliation. Alpha-hydroxy acids and lactic acid exfoliants will do the job, and sunscreen, when you go outdoors followed by curcumin creams when you get back indoors, will help keep seborrheic away in the future.