Seborrheic Keratosis: What It Is and How to Treat It

You've probably noticed them on your skin or someone else's: waxy, slightly raised spots that look like they've been stuck on with glue. They're often brown or tan, sometimes rough to the touch, and they multiply as the years go by. They're called seborrheic keratoses, and while they're completely harmless, they're one of the most common reasons people visit a dermatologist asking, "Is this something I should worry about?"

Key Takeaways

• Seborrheic keratoses are benign growths caused by keratinocyte overgrowth, not cancer.
• They have a distinctive "stuck-on" appearance and don't grow into the skin.
• Unlike actinic keratosis, seborrheic keratosis has no cancer risk or sun damage link.
• Melanoma can sometimes mimic seborrheic keratosis, making professional evaluation important.
• Treatment is optional and cosmetic; removal methods include cryotherapy and electrosurgery.
• Genetics and aging drive their development, not hygiene or lifestyle factors.
• Multiple sudden growths may signal an internal condition requiring medical attention.

What Seborrheic Keratosis Actually Is (and Where It Starts)

Seborrheic keratosis is a benign overgrowth of keratinocytes, the cells that make up the outermost layer of your skin. Think of it as your skin's version of a traffic jam: cells that normally shed and renew themselves start piling up instead, forming a raised, waxy lesion. These growths don't penetrate deeper layers of skin. They sit on the surface, which is why they often look and feel like they've been glued on.

The exact trigger isn't fully understood, but genetics play a significant role. If your parents had them, you're more likely to develop them too. Age is the strongest predictor:

• Seborrheic keratoses are rare before age 30 but become increasingly common after 50.
• By age 70, most people have at least a few of these growths.
• Unlike actinic keratosis, which is driven by cumulative sun damage and carries precancerous risk, seborrheic keratosis has no established link to UV exposure.
• They carry no malignant potential and are purely a marker of skin aging, not skin damage.

How Seborrheic Keratosis Differs From Other Skin Growths

Actinic keratosis vs seborrheic keratosis

Actinic keratosis vs seborrheic keratosis is a common source of confusion because both appear as rough, scaly patches on aging skin. But they're fundamentally different. Actinic keratoses are precancerous lesions caused by years of sun exposure. They feel rough and sandpaper-like, are usually pink or red, and develop on sun-exposed areas like the face, scalp, and hands. Left untreated, a small percentage can progress to squamous cell carcinoma. Seborrheic keratoses, by contrast, are benign, have a waxy or greasy texture, and can appear anywhere on the body (including areas that never see the sun). They don't transform into cancer.

Seborrheic keratosis vs melanoma pictures

This is where things get tricky. When comparing seborrheic keratosis vs melanoma pictures, you'll notice that seborrheic keratoses can sometimes look alarmingly similar to melanoma, especially when they're darkly pigmented or have irregular borders. The key difference: seborrheic keratoses have a "stuck-on" appearance with well-defined edges and consistent color throughout. Melanomas grow into the skin, often have asymmetric shapes, multiple colors within the same lesion, and borders that blur into surrounding skin. If a growth changes rapidly, bleeds without trauma, or has features that don't fit the classic seborrheic keratosis pattern, it warrants a biopsy. Dermoscopy (a tool dermatologists use to examine skin lesions under magnification) can often distinguish the two, but when in doubt, tissue diagnosis is the standard.

What Drives the Development of Seborrheic Keratosis

The primary driver is aging. As skin cells slow their turnover rate, keratinocytes accumulate rather than shedding efficiently. Genetic predisposition amplifies this: mutations in the FGFR3 and PIK3CA genes have been identified in seborrheic keratoses, suggesting that these growths result from clonal expansion of cells with specific genetic changes. This is not the same as inherited cancer risk; it's a localized, benign process.

Hormonal shifts may also play a role:

• Seborrheic keratoses sometimes appear or multiply during pregnancy, suggesting that estrogen or other hormonal changes influence keratinocyte behavior.
• Friction from clothing or skin folds can cause existing lesions to become irritated, inflamed, or itchy, but it doesn't cause new ones to form.
• There's no evidence that diet, hygiene, or topical products influence their development.
• They're not caused by poor skin care, and scrubbing them won't make them go away.

Why Some People Get More Than Others

If you have dozens of seborrheic keratoses while your sibling has none, genetics are likely the reason. Family history is the strongest predictor of both the number and age of onset. Some people develop their first lesion in their 30s; others don't see any until their 60s. Skin type doesn't seem to matter: seborrheic keratoses occur across all ethnicities and phototypes, though they may appear darker in individuals with more melanin.

Immune function may also play a subtle role. People with conditions that affect immune regulation (such as HIV or those on immunosuppressive therapy) sometimes develop seborrheic keratoses earlier or in greater numbers. This suggests that immune surveillance of abnormal keratinocyte clones may normally keep these growths in check. When that surveillance weakens, the growths proliferate.

When Skin Symptoms Point to Something Systemic

In rare cases, the sudden appearance of multiple seborrheic keratoses (especially if they're itchy or inflamed) can signal an internal malignancy. This phenomenon is called the Leser-Trelat sign, and it's most commonly associated with gastrointestinal cancers, particularly adenocarcinomas of the stomach, colon, or pancreas. The mechanism isn't fully understood, but it's thought that tumor-secreted growth factors stimulate keratinocyte proliferation.

If you notice a rapid eruption of seborrheic keratoses over weeks to months, particularly if accompanied by unexplained weight loss, fatigue, or changes in bowel habits, it's worth investigating. This is not a common presentation, and most people with seborrheic keratoses have no underlying disease. But when the pattern is atypical, it's a signal to look deeper.

How to Remove Seborrheic Keratosis at Home (and Why You Shouldn't)

There's no shortage of home remedies circulating online about how to remove seborrheic keratosis at home: apple cider vinegar, hydrogen peroxide, tea tree oil, even duct tape. The logic is that these substances will "burn off" or irritate the growth until it falls off. The reality is that seborrheic keratoses are firmly attached to the skin, and attempting how to remove seborrheic keratosis at home often results in incomplete removal, scarring, infection, or worse (mistaking a melanoma for a benign growth and delaying diagnosis).

Professional removal is straightforward and low-risk:

• Cryotherapy with liquid nitrogen is the most common method: the lesion is frozen, causing it to blister and fall off over one to two weeks.
• Electrodesiccation and curettage involve scraping the growth off and cauterizing the base.
• Shave excision removes the lesion flush with the skin surface.
• Laser therapy is another option, particularly for lesions on the face where cosmetic outcome matters.
• The FDA has also approved a topical 40% hydrogen peroxide solution for in-office use, which causes the lesion to peel off over several weeks (over-the-counter hydrogen peroxide is far too weak to have any effect).

What Biomarkers Can Tell You When Skin Changes Persist

Seborrheic keratoses themselves don't require bloodwork. But if you're seeing rapid changes in your skin, multiple new growths, or lesions that don't fit the typical pattern, it's worth investigating whether something systemic is driving the change. A comprehensive metabolic panel can screen for liver or kidney dysfunction. High-sensitivity C-reactive protein and erythrocyte sedimentation rate can flag underlying inflammation. If there's concern for malignancy, tumor markers like CEA or CA 19-9 may be indicated, though these are not first-line tests for skin changes alone.

For individuals with a strong family history of skin growths or early-onset seborrheic keratoses, genetic testing for mutations in FGFR3 or PIK3CA isn't standard practice but may be considered in research settings. More commonly, tracking immune markers like lymphocyte count or neutrophil-to-lymphocyte ratio can provide insight into immune function, particularly in individuals with conditions that affect immune regulation.

Getting to the Root of What's Driving Your Skin

If seborrheic keratoses are multiplying faster than you'd expect, or if you're noticing other skin changes alongside them, Superpower's biomarker panel can help you understand what's happening beneath the surface. Tracking markers of inflammation, immune function, and metabolic health gives you a clearer picture of whether your skin changes are purely age-related or part of a broader systemic pattern. Skin is one of the most visible signals your biology produces, and understanding it at a systemic level helps you address root causes, not just surface symptoms.