Seborrheic Keratoses, Skin Tags, and the Other Barnacles of Aging: What These Benign Growths Actually Are, Which Removal Methods Leave a Mark, Why Freezing Is Riskier on Deeper Skin Tones, and the One Look-Alike That Has to Be Biopsied

There is a category of skin complaint that rarely makes it into a cosmetic surgery brochure and fills a surprising share of dermatology appointments anyway. It is the collection of raised, benign spots that accumulate with age: the brown, waxy patch on the temple that looks like a drop of candle wax someone forgot to wipe off, the soft little flaps of skin where a necklace or a bra strap rubs, the cluster of tiny dark bumps on the cheekbones, the pale yellow domes on the forehead that catch the light in photographs. Patients describe them as barnacles, as age spots, as "those things," and very often as moles, which most of them are not.

They have names. The waxy brown patch is a seborrheic keratosis. The soft flap is a skin tag, which doctors call an acrochordon. The small dark bumps on the cheeks of many patients with brown and black skin are dermatosis papulosa nigra, usually considered a close relative of the seborrheic keratosis. The yellow domes are sebaceous hyperplasia, overgrown oil glands. Each of them is harmless, each of them is common, and each of them responds to a different set of removal techniques with a different set of tradeoffs.

The companion piece on cosmetic mole removal deals with true moles, which are colonies of pigment cells and carry a different set of questions. This piece is about everything else on that list: what each growth actually is, how removal works, what it costs in pigment and texture, and the narrow set of circumstances in which a spot that looks like a barnacle needs to go to a pathologist instead of into the trash. It is general information, not a diagnosis. A new, changing, bleeding, or unusual spot belongs in front of a dermatologist.

What these growths actually are, and why they multiply after forty

The short answer: seborrheic keratoses are benign overgrowths of the skin's surface cells, skin tags are soft folds of skin and fat that form where skin rubs, dermatosis papulosa nigra is a small, inherited variant of the seborrheic keratosis common in darker skin, and sebaceous hyperplasia is an enlarged oil gland, and none of them is precancerous.

Seborrheic keratoses are, by most accounts in the dermatology literature, the most common benign skin tumor in older adults. The American Academy of Dermatology describes them as growths that can look waxy, scaly, or slightly elevated, ranging from light tan to nearly black, with a characteristic "stuck on" appearance, as if they could be picked off with a fingernail. They grow from keratinocytes, the cells that make up the outer layer of the skin, not from the pigment cells that form moles. Their surface often has a rough, cracked, or warty texture, and many have tiny embedded plugs of keratin that look like seeds under magnification.

What causes them is only partly understood. They run in families, they become more numerous with every decade, and they appear on skin that sees little sun as well as skin that sees a lot, which is why sunlight is considered at most a contributing factor rather than the cause. Research has found recurring genetic changes inside the lesions themselves, but those changes keep the growth benign. A seborrheic keratosis does not turn into melanoma or any other skin cancer. That point is worth repeating, because the most common fear in the room is that the new brown spot is the beginning of something worse.

Skin tags are small, soft, skin-colored or slightly brown growths, often on a narrow stalk, made of a core of loose connective tissue and small blood vessels covered by skin. They favor the places where skin folds and rubs: the sides of the neck, the underarms, the eyelids, the groin, and under the breasts. They become more common with age and are associated in the medical literature with higher body weight, insulin resistance, and type 2 diabetes, which is why a person who suddenly develops many of them may reasonably have their blood sugar checked. The connection to glucose is one more reason the earlier piece on blood sugar and cosmetic surgery matters outside the operating room. They also appear or multiply in pregnancy, and some fade afterward.

Dermatosis papulosa nigra, usually shortened to DPN, appears as small, smooth, dark brown to black papules scattered across the cheeks, around the eyes, on the forehead, and sometimes on the neck. It is common in people of African descent and also occurs in people of Asian and Hispanic descent. It tends to start in young adulthood, runs strongly in families, and increases in number over time. Under the microscope it looks like a miniature seborrheic keratosis.

Sebaceous hyperplasia produces soft, yellowish or skin-colored bumps, usually a few millimeters across, on the forehead, nose, and cheeks of middle-aged and older adults. The giveaway is a small central dimple, called umbilication, where the oil gland opens. They are not cysts and they are not acne. They are simply oil glands that have grown larger than they used to be.

Two neighbors deserve a mention so they can be set aside. Cherry angiomas, the bright red dots that appear on the torso in middle age, are tiny clusters of blood vessels and are treated with vascular lasers and electrocautery, as covered in the piece on broken capillaries and facial redness. Flat brown sun spots, solar lentigines, are pigment problems rather than raised growths, and they belong to the lasers used for sun spots and pigmentation. Eyelid bumps such as xanthelasma and syringoma have their own logic, laid out in the piece on xanthelasma and syringoma.

How they come off: freezing, scraping, snipping, burning, and lasers

The short answer: most of these growths can be removed in a few minutes in an office with liquid nitrogen, a curette, small scissors, light electrocautery, or a laser, and the right choice depends on the type of growth, its thickness, its location, the patient's skin tone, and whether the tissue needs to be examined.

None of these growths requires an operating room, and almost none requires stitches. The methods overlap, and an experienced clinician will often combine them.

• Cryotherapy. Liquid nitrogen is sprayed or dabbed onto the lesion, freezing it. Over the following days the treated spot blisters or crusts and falls off, usually within a couple of weeks. It is fast, inexpensive, and effective for thin seborrheic keratoses and small skin tags. Its main drawback is that the cold destroys pigment cells as readily as the growth itself, which can leave a pale spot, and sometimes a darker ring around it.
• Curettage. The clinician numbs the area and uses a curette, a small, sharp, spoon-shaped instrument, to scrape the growth off the surface. Seborrheic keratoses sit on top of the skin and often lift off cleanly. Curettage has one advantage that freezing lacks: it produces tissue that can be sent to a lab.
• Shave removal. A thin blade shaves the lesion flush with the surrounding skin. It is used for thicker seborrheic keratoses and for any growth where a specimen is wanted.
• Snip excision. Skin tags on a narrow stalk are lifted and cut off at the base with sterile scissors. Very small tags often need little or no anesthetic, and a drop of a clotting solution or light cautery stops any bleeding.
• Electrodesiccation. A fine needle delivers a small electrical current that dries out the tissue. It is the workhorse for DPN and sebaceous hyperplasia, and it is often combined with curettage for thicker lesions. Settings matter a great deal: too much energy produces a scar or a pale spot.
• Lasers. Ablative lasers such as carbon dioxide and erbium can vaporize seborrheic keratoses and sebaceous hyperplasia, and certain pigment and vascular lasers are used for DPN. The tradeoffs are covered in more depth in the piece on ablative and non-ablative laser resurfacing.

For sebaceous hyperplasia there are also medical options. Topical retinoids may slow new lesions. Low-dose oral isotretinoin shrinks them while it is being taken, but they generally return when it is stopped, and anyone considering it should know about the waiting period isotretinoin creates before other procedures. Photodynamic therapy has been used as well. In practice, electrodesiccation or laser treatment of the individual bumps is the most common approach, with the understanding that new ones are likely to appear.

A topical option for seborrheic keratoses existed briefly. A high-concentration hydrogen peroxide solution received FDA approval in 2017 for raised seborrheic keratoses, but it was later withdrawn from the market by its manufacturer, and it is not something patients will generally find today. What remains on the shelf is a large retail market of creams, pens, and kits sold for "removing" skin tags and growths at home, which the FDA has warned consumers about. Home methods that tie off skin tags with bands or thread, or burn them with acids, can cause infection, scarring, and incomplete removal, and they skip the step that matters most, which is someone confirming what the growth actually is.

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The growth itself is harmless. The removal is where the risk lives: a pale spot that never repigments, a dark ring that takes a year to fade, or a melanoma that was frozen off without anyone ever looking at it under a microscope.

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Why freezing behaves differently on deeper skin, and what DPN removal really involves

The short answer: pigment cells are especially sensitive to cold, so cryotherapy can leave a permanent light spot on brown and black skin, and even gentle electrocautery or laser treatment can cause darkening that lasts for months, which is why DPN and other growths on deeper skin tones call for conservative settings, test spots, and an honest conversation about pigment change before the first lesion is touched.

Every removal method injures the skin around the growth to some degree, and skin responds to injury with pigment change. On fair skin that change is usually a faint pink or pale spot that blends over time. On deeper skin tones the response is often stronger and more visible.

Two patterns dominate. Hypopigmentation, a lighter patch, happens when the melanocytes in the treated area are damaged or destroyed. Liquid nitrogen is the classic cause because melanocytes are more sensitive to freezing than the surrounding cells. On brown skin a pale circle where a seborrheic keratosis used to be can be more noticeable than the original growth, and it may not repigment. Post-inflammatory hyperpigmentation, a darker patch, happens when inflammation stimulates the remaining pigment cells to overproduce. It can follow any of the methods, including electrodesiccation and lasers, and while it usually fades, it can take many months. The general principles are covered in the piece on cosmetic procedures on deeper skin tones, and the overlap with melasma is worth knowing for patients prone to both.

DPN illustrates the problem perfectly. A patient may have dozens of small papules across both cheeks, each one only a millimeter or two across, and the request is to remove all of them. Done well, light electrodesiccation, gentle curettage, or snip removal of each papule, at conservative settings, produces smooth skin with minimal pigment change. Done aggressively, it can leave a field of small pale or dark dots that is harder to live with than the original bumps. Many dermatologists who treat DPN regularly start with a small test area, wait several weeks to see how the skin responds, and only then treat the rest. Freezing is generally avoided.

There are also realistic expectations to set. DPN and seborrheic keratoses are lifelong tendencies, so new lesions will continue to form even after successful removal. Treated lesions occasionally recur. Strict sun protection in the weeks after treatment lowers the risk of darkening, and some clinicians use a brightening cream before and after treatment in patients who are prone to it. The same principles apply to patients who have had chemical peels or laser treatments in the past and know how their skin reacts: that history is the most useful predictor of how they will respond.

The look-alikes that matter, and why some of these should be biopsied

The short answer: most of these growths are diagnosed reliably by eye and with a dermatoscope, but melanoma can imitate a seborrheic keratosis, basal cell carcinoma can imitate sebaceous hyperplasia, and a sudden eruption of many new seborrheic keratoses is occasionally a sign of internal disease, so any lesion that looks atypical, is changing, or does not behave like its neighbors should be sampled rather than destroyed.

The reason a trained eye should look first is not that these growths are dangerous. It is that a handful of dangerous growths look like them.

Melanoma that looks like a seborrheic keratosis. Some melanomas grow with a rough, raised, warty surface that can pass for a seborrheic keratosis to an untrained or hurried eye. Dermatologists use a dermatoscope, a lighted magnifying device, to look for the structures that distinguish the two, such as the milia-like cysts and comedo-like openings typical of a seborrheic keratosis. When there is genuine doubt, the lesion is shaved or removed and sent to a lab. Freezing a lesion that turns out to be melanoma destroys the tissue needed to make the diagnosis and to judge how deep it went. The value of the specimen is explained in the piece on reading a pathology report after cosmetic surgery.

Basal cell carcinoma that looks like sebaceous hyperplasia. Both can appear as small, skin-colored bumps on the face with fine blood vessels on the surface. Basal cell carcinoma is typically pearly or translucent, may bleed or crust, and keeps growing. Sebaceous hyperplasia has its central dimple and a yellowish cast. A bump that bleeds, does not heal, or grows steadily is not treated as sebaceous hyperplasia until it has been examined. When a skin cancer does turn up on the face, the treatment and repair are covered in the piece on Mohs surgery and facial reconstruction.

The skin tag that is not a skin tag. Most soft, stalked growths in skin folds are exactly what they look like. But growths with an unusual color, growths that bleed without being irritated, growths in unusual places, and growths that are firm rather than soft deserve a closer look. Neurofibromas and some moles can be pedunculated. Growths near the eyelid margin, already covered in the piece on chalazion and stye, call for particular care, both for diagnosis and for removal so close to the eye.

The sudden eruption. The sign of Leser-Trélat refers to a rapid increase in the number and size of seborrheic keratoses, sometimes with itching, in association with an internal cancer, most often of the digestive tract. It is rare, and its significance is debated, because seborrheic keratoses are so common that some apparent associations may be coincidence. But a sudden shower of new growths over weeks to months, rather than the slow accumulation of years, is a reason to see a physician rather than simply book a removal appointment.

This is the core argument for having a physician, and preferably a dermatologist, examine these growths before anyone removes them, even if the removal itself is done by a trained clinician under supervision. The concern about who is actually performing treatment is the same one raised in the piece on med spa supervision. Plasma pens and other devices promoted for removing skin tags and spots outside medical settings have been associated with burns, scarring, and pigment changes, and none of them involves looking at the lesion under a microscope.

Insurance, cost, and what to expect afterward

The short answer: removal for appearance alone is almost never covered by insurance, removal of growths that are bleeding, inflamed, itching, repeatedly irritated, or diagnostically uncertain often is, and recovery is usually a week or two of small scabs followed by weeks to months of pink, light, or dark marks that gradually settle.

Insurers draw a line between cosmetic removal and medically necessary removal, and that line runs through the middle of this topic. A seborrheic keratosis removed because it is unsightly is cosmetic. A seborrheic keratosis that bleeds when it catches on clothing, that is chronically inflamed or itchy, that is in a location where it is repeatedly traumatized, or that cannot be confidently diagnosed without a biopsy may be covered, and Medicare and many private plans have written policies describing the documentation they require. The broader logic is laid out in the piece on when insurance covers plastic surgery. Patients should expect their dermatologist to document symptoms honestly and should not expect a cosmetic request to be coded as medical.

For cosmetic removal, practices price in different ways: per lesion, per treatment session, or in tiers based on the number of lesions. A session to remove dozens of DPN papules or skin tags is generally priced as a block. The questions in the piece on what a cosmetic quote actually covers apply here in miniature: whether follow-up touch-ups are included, whether pathology fees are separate, and whether the price changes if more lesions are found on the day.

Recovery is simple but not instant.

• The first one to two weeks. Frozen lesions blister or darken and then crust. Scraped, shaved, or cauterized lesions leave a small raw spot that forms a scab. Gentle cleansing, a thin layer of petrolatum, and leaving the scabs alone are generally all that is needed. Picking them off early raises the risk of scarring and pigment change.
• The following weeks to months. Treated spots are typically pink at first, then gradually blend. Lighter or darker patches can persist, especially on deeper skin tones, and sun exposure makes darkening worse. Consistent sunscreen and sun avoidance on the treated areas matter more here than any specialty product. General principles for helping small wounds heal well are in the piece on scar care after plastic surgery.
• The long term. These are recurring tendencies, not one-time problems. Seborrheic keratoses, skin tags, DPN, and sebaceous hyperplasia will keep appearing over the years in people prone to them, and periodic touch-up sessions are part of the plan rather than a sign that the first treatment failed.

For patients considering larger cosmetic work, removing growths in the same area is often reasonable to discuss at the same consultation, though thicker or more extensive lesions and anything suspicious should be dealt with on their own terms first. Anyone weighing multiple opinions on an unusual lesion or an extensive treatment plan may find the framework in the piece on getting a second consultation useful, and the credential questions in the piece on board certifications apply as much to who is diagnosing a spot as to who is operating.

The honest summary

The raised spots that accumulate with age are, in almost every case, harmless. Seborrheic keratoses are benign overgrowths of the skin's surface cells with a waxy, stuck-on look. Skin tags are soft flaps of skin in places that rub, more common with higher body weight, insulin resistance, and pregnancy. Dermatosis papulosa nigra is a small, inherited relative of the seborrheic keratosis common on darker skin. Sebaceous hyperplasia is an enlarged oil gland with a telltale central dimple. None of them becomes cancer, and none of them has to be removed.

When people do want them removed, the choice of method matters more than the growth itself. Freezing is quick and inexpensive but can leave a permanent pale spot, especially on brown and black skin. Curettage, shave removal, snip excision, light electrodesiccation, and lasers each have their place, and conservative settings with a test area first are the sensible approach for anyone at risk of pigment change. New growths will keep coming, so periodic touch-ups are normal.

The one firm rule is diagnosis before destruction. Melanoma can masquerade as a seborrheic keratosis, basal cell carcinoma can pass for sebaceous hyperplasia, and a sudden shower of new growths can occasionally signal something internal. A dermatologist with a dermatoscope can tell the difference in most cases, and a lesion that looks wrong should be sampled and sent to a pathologist rather than frozen off. Home kits, plasma pens, and anyone willing to burn off a spot without looking at it closely skip exactly that step, which is the only step that was ever really protecting the patient.