Seborrheic Keratosis: Waxy Growths, Diagnosis, and Treatment
A seborrheic keratosis is a common, noncontagious skin growth that may look waxy, rough, or as if it is sitting on top of the skin. It can be tan, brown, gray, or nearly black, and many people develop more than one over time. These growths are usually harmless and often need no treatment.
Appearance alone cannot always separate a seborrheic keratosis from melanoma, basal cell carcinoma, squamous cell carcinoma, or other growths. If a spot is new, changing, repeatedly bleeding, not healing, or uncertain, have a healthcare professional examine it. Do not freeze, cut, or scrape a growth at home.
What is a seborrheic keratosis?
A seborrheic keratosis is a benign overgrowth of cells in the outer layer of skin. It may begin as a small, slightly rough spot and become more raised or thicker over time. Some have a waxy, warty, or “stuck-on” look; others are flat or only subtly rough. A person can have one lesion or many.
The name can be confusing. The growth does not come from oil-producing sebaceous glands, and it is not the same condition as seborrheic dermatitis. It is also not a viral wart and does not spread from person to person. Most do not cause health problems. However, a clinician may need to distinguish one from skin cancer if the appearance is atypical or changing.
Common appearance and where they develop
Color ranges from skin-colored or pale tan to brown, gray, or nearly black. Texture can be smooth, scaly, rough, or waxy. A lesion may be flat at first, then thicken; some develop small surface pits, ridges, or a crumbly scale. Sizes range from a few millimeters to several centimeters. Several lesions may appear in one area, while others are scattered across the body.
They can develop on many areas of skin, including the chest, back, abdomen, scalp, face, neck, and limbs. They are not expected on the palms or soles. Areas under clothing can also be affected, so their presence does not simply indicate a spot received too much sun. Friction can make a growth in a fold or under a clothing edge feel irritated.
Growths may appear tan, brown, gray, or black and may contrast clearly with nearby skin.
Color and contrast vary. Many small dark papules on the face or neck may be dermatosis papulosa nigra, a benign variant commonly seen in darker skin.
Small, rough, pale or gray “stucco” keratoses are one recognized variant. Other diagnoses can look similar, so uncertainty should be assessed.
These descriptions are general patterns, not a way to self-diagnose. A photo viewed online or a comparison with someone else’s spot cannot reliably identify an individual lesion, especially when pigment, surface, and lighting differ.
Causes, age, and family tendency
The exact cause is not fully understood. Seborrheic keratoses become more common with age and may run in families; a person who has one may develop more over time. They can also appear in younger adults. They are not caused by poor hygiene, and they are not contagious.
Although the name contains “seborrheic,” the growths are not produced by oil glands. They are also distinct from actinic keratoses, which are rough lesions associated with sun damage and may need medical treatment. Do not assume that a rough or scaly spot is harmless because another spot nearby was diagnosed as a seborrheic keratosis.
There is no established home routine that prevents these growths. Sun protection remains important for overall skin health, but sunscreen or exfoliation has not been shown to reliably prevent seborrheic keratoses. Scrubbing, picking, or applying an acid to a lesion can inflame or injure the skin without confirming what it is.
Symptoms and irritation
Most seborrheic keratoses cause no symptoms. Some itch, become tender, or feel rough when clothing or jewelry rubs against them. A growth can become inflamed and crusted after repeated friction or scratching. It may bleed after being caught or picked, but bleeding by itself cannot tell whether the lesion is benign.
A spot that starts bleeding without a clear injury, repeatedly bleeds, forms a sore that does not heal, grows rapidly, or changes noticeably should be examined. A clinician can determine whether irritation explains the symptom or whether sampling is appropriate.
When to have a spot checked
Arrange an appointment with a primary care clinician or dermatologist when you are not sure what a growth is, when a pigmented spot changes, or when it is bothersome enough that you are considering removal. An assessment is especially important for a growth that is growing quickly, changing in color or shape, becoming persistently painful or itchy, bleeding without repeated friction, ulcerating, or failing to heal.
Melanoma and other skin cancers can sometimes mimic a seborrheic keratosis. A cancer may also arise next to or within a benign keratosis by coincidence. Even clinicians may use a dermatoscope or biopsy when the appearance is not clear. Do not rely on whether a growth looks “stuck on,” whether it has been present for years, or whether a similar lesion was previously called benign.
Some people notice many new growths over a short period. A sudden eruption, particularly with itch or inflammation, is worth mentioning during a medical review. A rare association between eruptive seborrheic keratoses and an internal cancer has been described, but the finding is not diagnostic by itself and similar eruptions can occur without cancer. The clinician can consider the whole history and decide whether any further evaluation is warranted; do not order screening tests or assume a cancer diagnosis based on the skin pattern alone.
How clinicians diagnose seborrheic keratosis
A clinician asks when the spot appeared, whether it has changed, and whether it itches, hurts, catches on clothing, or bleeds. They inspect the lesion, often comparing it with other growths. A handheld dermatoscope magnifies surface structures that are not easy to see with the naked eye. This can help, but it does not make every lesion certain.
If the diagnosis is straightforward, a clinician may explain that no treatment is needed. If a growth looks atypical or resembles skin cancer, they may remove part or all of it and send tissue to a laboratory. A shave biopsy or curettage can sometimes both remove a lesion and provide tissue for examination. The procedure depends on the location, thickness, and diagnostic concern.
A skin biopsy is a common way to resolve uncertainty; it is not a sign that the clinician already believes the growth is cancer. The sample is examined under a microscope. If the result does not match the appearance or symptoms, the clinician may arrange follow-up or another procedure.
Treatment and removal options
Most confirmed seborrheic keratoses do not need treatment. A person may choose removal if a growth repeatedly catches on clothing, is irritated or itchy, interferes with shaving or jewelry, or is bothersome in appearance. Removal may also be part of diagnosis when the lesion is uncertain. If testing is needed, ask whether the chosen method will provide a tissue sample.
Cryotherapy uses liquid nitrogen to freeze the growth. It is often used for thinner lesions. The area may blister or crust before healing, and a thicker growth may need another approach. Lighter or darker pigment can remain, sometimes permanently.
Shave removal or curettage removes the raised portion with a blade or scraping instrument, usually after numbing the area. It can be useful when a sample is needed for examination. Electrocautery uses controlled electrical energy to destroy tissue and may be combined with scraping. Some clinics may offer laser or other methods for selected lesions.
No method suits every lesion. Risks include discomfort, bleeding, infection, scarring, and a lighter or darker mark. Pigment changes can be more noticeable in brown or Black skin, and methods that remove tissue can leave a shallow scar. A treated spot may not return, but new growths can appear elsewhere; occasionally a lesion can recur at the same site.
Liquid nitrogen; often selected for thinner lesions. Blistering and pigment change are possible.
Removes raised tissue and can supply a sample when diagnosis is uncertain.
Uses electrical energy, sometimes together with curettage. Scarring and pigment change remain possible.
Discuss the location, skin tone, desired cosmetic result, chance of a specimen, healing time, aftercare, and cost before a cosmetic removal. A lesion on the eyelid, face, or another delicate area may need a clinician experienced with that location. For an uncertain spot, diagnostic safety comes before choosing a cosmetic technique.
Why home removal is not a safe shortcut
Do not cut, shave, scrape, burn, tie off, or freeze a growth yourself. Over-the-counter wart treatments are not a reliable way to identify or treat a seborrheic keratosis. Acids, household remedies, and home freezing can damage surrounding skin, cause infection or scarring, and make later examination harder. More importantly, treating a spot you assume is benign can delay diagnosis of a skin cancer.
If clothing rubs the area, try a soft fabric layer and avoid picking at the surface. If it becomes irritated, a clinician can check for inflammation, confirm what the growth is, and discuss appropriate care. Avoid applying a harsh exfoliant or an unprescribed treatment directly to a changing lesion.
What to expect after removal
After a procedure, follow the instructions given by the clinician who treated the area. Depending on the method, the site may blister, form a small scab, or need simple wound care. Keep it clean and avoid picking while it heals. Ask what amount of redness, soreness, or drainage is expected and how long to protect the area.
Contact the clinic if pain, redness, warmth, or swelling is increasing, if there is pus, or if the wound is not healing as expected. After a biopsy, ask when and how you will receive results. If the spot returns or changes at the treated site, arrange a review; new seborrheic keratoses can also develop elsewhere and do not necessarily mean the first procedure failed.
Outlook
Seborrheic keratoses are usually long-term benign growths. Some stay much the same, some slowly become thicker, and a few may become inflamed or fade. New ones may appear with age. There is no need to remove every lesion, and a confirmed typical growth does not require repeated treatment simply because it remains visible.
When a spot is uncertain, changing, painful, or bleeding, assessment is the useful next step. Reassurance after examination can prevent unnecessary procedures; biopsy can provide clarity when the appearance is not typical. Choose any removal after discussing the purpose, benefits, and possible pigment or scar changes.
Small dark papules and dermatosis papulosa nigra
Dermatosis papulosa nigra is a benign seborrheic keratosis variant that often appears as numerous small, dark, slightly raised papules on the face or neck. It is seen more often in people with darker skin tones and can run in families. The papules may be longstanding and occur in clusters, but a clinician should assess a spot that is new, changing, symptomatic, or different from the others.
People sometimes mistake these growths for dirt, clogged pores, or warts. Scrubbing will not remove them and may irritate the skin. If the appearance bothers you or a papule catches on clothing or jewelry, a dermatologist can discuss whether treatment is appropriate. Removal can cause lighter or darker marks, which may be noticeable against surrounding skin. Ask about the risk for your skin tone and the likelihood that new papules will appear later.
Prepare for an appointment
A short history can make a skin-growth visit more useful. Note roughly when you first saw the spot, whether it has changed in size, height, color, or surface, and whether it itches, hurts, catches on clothing, or bleeds. If it has changed, a dated photo taken before the visit may help show the timeline. A photo is only supporting information; it cannot replace a hands-on examination.
Tell the clinician if you have had skin cancer or biopsies before, whether other growths appeared at the same time, and whether a spot was repeatedly injured by shaving, jewelry, or a clothing seam. Bring a list of your concerns, including whether removal is for comfort, diagnosis, or appearance.
Useful questions include: Does this look typical, or would a dermatoscope or biopsy help? If it is removed, will tissue be sent for examination? What type of scar or pigment change is possible on this site and skin tone? How should the wound be cared for, when will results be available, and what changes should prompt a return visit? If removal is cosmetic, ask about expected results, cost, and whether a new growth could appear elsewhere.
Frequently asked questions
Are seborrheic keratoses contagious or caused by a virus?
No. A seborrheic keratosis is a benign growth of skin cells. It is not contagious, is not a viral wart, and is not caused by poor hygiene.
Can a seborrheic keratosis turn into skin cancer?
A typical seborrheic keratosis is benign and does not usually become cancer. The challenge is that melanoma and other skin cancers can look similar, and a cancer can rarely occur beside or within a keratosis. Have a new, changing, bleeding, or uncertain spot checked instead of diagnosing it at home.
Do seborrheic keratoses need treatment?
Usually not. A clinician may recommend removal if the spot is irritated, catches on clothing, is bothersome, or needs sampling because the diagnosis is uncertain. Removal is also sometimes chosen for appearance after the diagnosis and risks are discussed.
Can I freeze or scrape one off at home?
No. Home freezing kits, acids, scraping, and cutting can injure skin, cause infection or scarring, and delay diagnosis of a growth that is not a seborrheic keratosis. A clinician can identify the lesion and use an appropriate procedure.
Why do they appear, and can I prevent them?
The exact cause is not known. They become more common with age and may run in families. There is no established way to prevent them, and they are not a sign of poor hygiene.
What does it mean if many appear quickly?
Several new growths can occur over time for benign reasons. A sudden crop of many lesions, especially if itchy or inflamed, is worth discussing with a clinician. A rare association with internal illness has been described, but this pattern alone does not diagnose cancer and can also occur without it.
Can removal leave a scar or a lighter or darker mark?
Yes. Freezing or scraping can leave temporary or lasting pigment change, and any procedure can scar or bleed. The chance depends on the lesion, method, skin, and healing. Ask the clinician to compare options and expected pigment changes for your skin tone.
References and further reading
- American Academy of Dermatology. Seborrheic keratoses: Signs and symptoms.
- American Academy of Dermatology. Seborrheic keratoses: Diagnosis and treatment.
- DermNet. Seborrhoeic keratoses: causes, appearance, diagnosis, and treatment.
- British Association of Dermatologists. Seborrhoeic keratosis patient information leaflet.
- Mayo Clinic. Seborrheic keratosis: diagnosis and treatment.
- Mayo Clinic. Seborrheic keratosis: symptoms and causes.
Medical information notice: This article is for general education and does not replace diagnosis or treatment. A new or changing skin growth should be assessed by a qualified clinician. Do not attempt to remove a growth at home.
0 comments