Is a seborrheic keratosis dangerous or cancerous?

No. A seborrheic keratosis is a benign, noncancerous growth and is one of the most common skin growths in older adults. The concern is that it can look like skin cancers such as melanoma, so a new or changing spot should be checked by a dermatologist to be sure.

Can seborrheic keratoses go away on their own?

They generally do not disappear on their own. They are a long-term, harmless feature of aging skin. They can be removed in-office for cosmetic reasons or if they become irritated, but there is no medical need to treat them.

How can I tell a seborrheic keratosis from a melanoma?

You often can't reliably tell at home, which is the whole point of getting it checked. Seborrheic keratoses typically have a waxy, 'stuck-on' look, while melanomas tend to be flat with irregular borders and uneven color. Because the two can overlap, a dermatologist evaluation, and sometimes a biopsy, is the safe way to know.

Should I be worried if I suddenly get a lot of them?

A sudden eruption of many seborrheic keratoses, known as the sign of Leser-Trelat, is worth getting evaluated promptly. Researchers debate whether it signals an internal cancer, and the evidence for that link is not strong, but a quick crop of new spots is a good reason to see a clinician.

Can I remove a seborrheic keratosis at home?

No. Cutting, burning, freezing, or picking at a growth yourself risks infection, scarring, and bleeding, and it removes the chance to have the spot properly evaluated. Removal should be done by a clinician who can confirm the diagnosis first.

Learning›Science of Skin

Seborrheic Keratosis: What That "Stuck-On" Brown Spot Really Is

June 10, 2026

You noticed a new brown, waxy spot on your back or chest, and it looks like it was glued onto your skin. Maybe it caught on your clothing, or maybe you're worried it could be skin cancer. Most of the time, a growth like this is a seborrheic keratosis: one of the most common and most harmless skin growths there is.

Still, a new or changing spot deserves a careful look, because seborrheic keratoses can be mistaken for more serious things. Here is what they are, why they show up, and the signs that mean you should get a spot checked.

What is a seborrheic keratosis?

A seborrheic keratosis is a noncancerous (benign) skin growth, made up of immature skin cells called keratinocytes. It is the most common benign growth of the outer skin layer, and it becomes far more common with age. It is not contagious and is not a form of skin cancer.

You may hear it called by other names, including SK, basal cell papilloma, senile wart, or even a 'barnacle.' Despite the 'wart' nicknames, a seborrheic keratosis is not caused by a virus the way a true wart is. Some people develop just one or two over a lifetime; others develop dozens or even hundreds.

Benign (noncancerous) and not contagious
Made of immature skin cells (keratinocytes)
More common with age, often inherited
Not the same as a viral wart

What does a seborrheic keratosis look like?

The classic clue is a 'pasted on' or 'stuck-on' appearance, as if the spot were sitting on top of the skin rather than growing out of it. Lesions are usually waxy or scaly, slightly raised, and round or oval. Most are tan or brown, but they can range from white to black, and sizes run from very small to more than an inch across.

They can appear almost anywhere except the palms and soles, most often on the chest, back, head, or neck, and also the face. They are usually painless, though they can itch. Because they range in color and texture, they are sometimes confused with warts or, more concerningly, with skin cancers such as melanoma. That overlap is exactly why a dermatologist's eye matters.

A waxy or scaly bump with a 'stuck-on' look
Tan or brown most often, but white to black possible
From very small to over 1 inch
Common on the chest, back, head, neck, and face
Usually painless but may itch

What causes them, and who gets them?

The exact cause isn't fully understood, but seborrheic keratoses come from a harmless overgrowth of skin cells. Sporadic lesions commonly carry activating mutations in a gene called fibroblast growth factor receptor-3 (FGFR3), which helps drive that benign growth. They tend to run in families, pointing to an inherited tendency.

Age is the biggest factor. The peak time for developing them is after age 50, and they are extremely common in older adults: estimates suggest they develop in 88% of adults aged 64 and older, and nearly all adults over 60 have at least one. They are essentially a normal sign of skin aging, not a sign that anything is wrong.

Do they need to be removed or treated?

Because seborrheic keratoses are harmless, most do not need any treatment at all. The main reasons people choose removal are cosmetic, or because a growth gets irritated, itchy, or repeatedly catches and bleeds on clothing or jewelry. An irritated, inflamed lesion can be uncomfortable and is one reason to see a clinician.

If you and your dermatologist decide to remove one, it is typically done in-office with methods such as freezing (cryotherapy), gentle scraping or shaving, or other surface techniques. Importantly, do not try to cut, burn, or pick a growth off yourself. You risk infection, scarring, and bleeding, and you lose the chance to have it properly evaluated if it turns out not to be a simple seborrheic keratosis.

When should you see a doctor?

Because a seborrheic keratosis can resemble melanoma and other skin cancers, the safest rule is to have any new, changing, or unusual spot evaluated. A dermatologist can usually diagnose one by sight or with a dermatoscope, looking for telltale features like keratin-filled crevices and a brain-like ridge-and-furrow pattern. If there is any doubt, a small shave or punch biopsy can confirm it.

Pay attention to a single spot that grows quickly, changes color, has irregular or blurred borders, bleeds, or simply looks different from your other growths. One more pattern is worth knowing: the sudden eruption of many seborrheic keratoses at once, sometimes itchy, is called the sign of Leser-Trelat. Researchers have debated whether it can signal an internal cancer; one meta-analysis found an association that did not reach statistical significance (pooled odds ratio 3.91, 95% CI 0.72 to 21.19), with seborrheic keratosis prevalence of 26.9% in gastrointestinal-cancer cases versus 15.4% in controls. The takeaway is not to panic, but to get a sudden crop of new spots checked promptly.

A spot that grows fast, bleeds, or changes color
Irregular, blurred, or uneven borders
A growth that looks different from your others
A sudden eruption of many new spots at once
Any new spot you simply aren't sure about

Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider before starting any new skincare treatment, especially if you have underlying health conditions, are pregnant, or are taking medications.