✅ What you’ll learn from this article:
- Causes and symptoms of seborrheic keratosis
- Effective treatment options (including insurance-covered treatments)
- Are over-the-counter products effective?
- Prevention methods and daily skin care
- ⚠️ If left untreated, lesions may enlarge and catch on clothing, causing bleeding…
💡 Do any of these concerns sound familiar?
“I’ve noticed small bumpy warts appearing on my face or neck…”
“Are these age warts? Can I remove them myself?“
“Can over-the-counter products help, or should I see a doctor?”
📢 If left untreated, they may grow larger over time!
Seborrheic keratosis, also known as “age warts,” refers to warts that tend to develop more frequently as you age. However, warts can also appear around the neck and temples even in people in their 20s.
🔍 What Is Seborrheic Keratosis?
Seborrheic keratosis is a wart-like skin condition also known as “age warts” [1,2,3]. Formally called “seborrheic keratosis,” it is known as one of the most common benign skin tumors [2,10].
📊 Worldwide, it is an extremely frequent skin lesion observed in approximately 80% or more of adults aged 40 and over [2,4].
It can appear anywhere on the body, but is particularly common on the face and neck [1,12]. Epidemiological studies report that some form of seborrheic keratosis is found in approximately 90% of people aged 60 and over, and in nearly 100% of those aged 80 and over [4,8].
📍 Most commonly affected sites:
- 😟 Face (approximately 60%) – often the most noticeable area
- 👕 Trunk (approximately 30%) – areas covered by clothing
- 🙋 Neck (approximately 20%) – a highly visible location
📏 Lesions range from about 2 mm to 2 cm in size and are round or oval in shape. The surface is either smooth or rough, and there is no pain.
⚠️ However, seborrheic keratosis grows larger over time, and enlarged lesions may bleed or become inflamed when caught on fingers or clothing.
🌞 What Causes Seborrheic Keratosis?
The primary cause of seborrheic keratosis is ultraviolet (UV) radiation [1,4,8].
Prolonged sun exposure causes UV-induced abnormalities in the skin’s DNA. At the molecular level, activating mutations in genes such as FGFR3, PIK3CA, and RAS are frequently detected and are considered responsible for the abnormal proliferation of epidermal keratinocytes [3,12]. A decline in the skin’s antioxidant capacity associated with aging is also thought to contribute to the condition [3].
Cells with these abnormalities proliferate and cause the skin to become raised. They also stimulate pigment cells, leading to darker coloration.
⚠️ Those who should take particular care:
- ⛱️ Those who play sports or work outdoors
- 🌅 Those with fair skin who do not wear makeup or sunscreen when going outside
- 🏖️ Those who use tanning salons
In addition, genetics is thought to influence an individual’s likelihood of developing seborrheic keratosis.
🏥 How Is Seborrheic Keratosis Diagnosed?
In most cases, seborrheic keratosis can be diagnosed by visual examination alone.
However, when the presentation is atypical or uncertain, the following steps are taken:
- 📝 Medical interview: Review of symptoms and medical history
- 👀 Examination: Visual inspection of the affected area
- 🔬 Testing: Detailed observation of the affected area using a dermatoscope (magnifying instrument) [11,13,14,22]Dermoscopy can reveal findings characteristic of seborrheic keratosis, such as a gyrus-like pattern, comedo-like openings, and milia-like cysts [11,22]. These findings allow differential diagnosis from malignant melanoma and basal cell carcinoma, significantly improving diagnostic accuracy [13,14].
If a diagnosis still cannot be made, a small sample of skin tissue may be removed for histopathological examination.
💊 Should You Remove Seborrheic Keratosis Yourself? Treatment Options
🚫 Do not attempt to remove it yourself under any circumstances!
If you develop seborrheic keratosis, do not attempt to remove it yourself—please consult a physician. Self-removal may lead to recurrence or infection. Since seborrheic keratosis is technically not a wart, over-the-counter wart treatments are unlikely to be effective.
✅ The main treatment options for seborrheic keratosis are the following three:
- ❄️ Liquid nitrogen (cryotherapy)
- ✨ Laser treatment
- 🔪 Surgical treatment
Each treatment option is described below.
❄️ Treatment Option (1): Liquid Nitrogen Cryotherapy (Insurance-Covered)
One treatment option for seborrheic keratosis is cryotherapy with liquid nitrogen [5,12,16].
Cryotherapy is internationally recommended as a first-line treatment for seborrheic keratosis, with a treatment success rate of approximately 85–90% reported [5]. Liquid nitrogen at −196°C freezes the lesion, causing cell destruction through the formation of intracellular ice crystals [16].
💰 This treatment is available at most dermatology clinics and is relatively affordable. However, it is associated with significant discomfort both during and after the procedure.
⚠️ A notable drawback is that post-inflammatory hyperpigmentation at the treated site may persist for approximately six months to two years.
✨ Treatment Option (2): Laser Treatment (Not Covered by Insurance)
Seborrheic keratosis can also be treated with laser therapy.
The differences between laser types are as follows:
| Laser Type | Features |
|---|---|
| 💡 CO2 Laser | ✅ Can treat lesions regardless of how raised they are ✅ Post-treatment hyperpigmentation typically resolves within a few months |
| 🌟 Q-Switched Laser | ✅ Suitable only for lesions with minimal raised surface ✅ Less likely to leave scarring after treatment |
※ The treatment outcome data above are based on large-scale clinical studies [5,16,17].
😊 Laser treatment offers the advantage of minimal discomfort and fewer treatment marks [17,18,24,25]. CO2 laser enables precise ablation through selective tissue vaporization, minimizing thermal damage to surrounding tissue [17,24]. Q-switched laser achieves excellent results for flat lesions through selective pigment destruction [24,25].
💸 However, please note that the risk of recurrence is relatively higher, and laser treatment is not covered by insurance, meaning the full cost is paid out of pocket.
🔪 Treatment Option (3): Surgical Treatment (Insurance-Covered)
Seborrheic keratosis can also be treated with surgical procedures.
Surgical treatment involves methods such as excision with a scalpel or electrocautery with an electric scalpel. However, since the risk of recurrence is relatively higher and scarring is possible, it is not typically recommended as a first choice.
Surgical treatment may be considered when malignancy is suspected.
💊 Can Over-the-Counter Wart Treatments Remove Seborrheic Keratosis?
🚫 Over-the-counter wart treatments cannot remove seborrheic keratosis.
Ordinary warts are typically caused by a virus. However, seborrheic keratosis is a benign skin tumor and is technically not a wart.
As there are no medications expected to be effective against seborrheic keratosis, self-treatment is not a viable option.
Please seek medical consultation rather than attempting to treat it with medication.
🛡️ Can Seborrheic Keratosis Be Prevented?
To help reduce the risk of seborrheic keratosis, protecting your skin from UV radiation is important [4,8,12].
📊 Epidemiological studies have found a strong correlation between lifetime UV exposure and the incidence of seborrheic keratosis, with regular use of sunscreen (SPF 30 or higher) reported to help reduce the risk of developing the condition by approximately 40–50% [4,8].
☀️ Even younger individuals should apply sunscreen to exposed areas when engaging in outdoor sports or activities.
🏠 Additionally, wearing a low-irritant sunscreen even when indoors is recommended.
⚠️ Possibility of Malignant Transformation
Malignant transformation of seborrheic keratosis is extremely rare; however, caution is warranted if rapid changes occur, such as sudden enlargement, ulceration, or changes in color [1,12,15].
In addition, multiple seborrheic keratoses (the Leser–Trélat sign) are known to be a cutaneous manifestation of internal malignancy, and internal medical investigation is recommended in such cases [12,15].
📈 Epidemiology and Incidence of Seborrheic Keratosis
Seborrheic keratosis is the most frequently occurring benign skin tumor, and its incidence rises sharply with age [2,4].
📊 Incidence by age group:
- 🔹 Aged 40 and over: approximately 80%
- 🔹 Aged 60 and over: approximately 90%
- 🔹 Aged 80 and over: nearly 100%
There is little difference between the sexes, but the incidence is reported to be approximately 2–3 times higher in occupations with high sun exposure, such as outdoor workers [8]. Regionally, particularly high prevalence rates have been reported in Australia and Southern Europe, where UV intensity is high [4].
🔬 Dermoscopic Diagnosis and Differential Diagnosis
Dermoscopy is an essential diagnostic tool for seborrheic keratosis [11,13,14,22].
🔍 Typical findings:
- 🧠 Gyrus-like pattern
- ⚫ Comedo-like openings
- 🔘 Milia-like cysts
- 📍 Keratin plugs
These findings allow differentiation from malignant melanoma, basal cell carcinoma, and pigmented nevi [13,14]. Dermoscopic examination has been reported to improve diagnostic accuracy by approximately 20–30% compared with naked-eye examination [14].
🧬 Molecular Biology of Seborrheic Keratosis
Multiple gene mutations are involved in the development of seborrheic keratosis [3,12].
🧬 Most frequently detected mutations:
- FGFR3: approximately 85%
- PIK3CA: approximately 20%
- RAS genes: approximately 15%
Activating mutations in these genes are thought to cause abnormal proliferation of epidermal keratinocytes [3].
Inactivation of the p16/CDKN2A gene and abnormalities in the Wnt signaling pathway have also been found to contribute to the condition [3,12].
These molecular biological findings provide important insights for the future development of molecularly targeted therapies [3].
📊 Post-Treatment Course and Long-Term Prognosis
With appropriate treatment, the prognosis for seborrheic keratosis is generally favorable [5,16].
✅ Complete clearance rates by treatment method:
- ❄️ Liquid nitrogen cryotherapy: approximately 85–90%
- ✨ CO2 laser treatment: approximately 95% or higher
Recurrence rates vary by treatment method: below 1% with complete excision, and approximately 5–10% with superficial treatments [5,16].
⏰ Post-treatment hyperpigmentation:
- ❄️ Liquid nitrogen: improves within 3–12 months
- ✨ Laser treatment: improves within 1–3 months
The long-term risk of malignant transformation is very low, and appropriate treatment may help improve quality of life [12].
❓ Frequently Asked Questions about Seborrheic Keratosis
Here are answers to frequently asked questions about seborrheic keratosis.
🚫 Wood vinegar cannot remove seborrheic keratosis [1,12]. There is no medical evidence supporting its effectiveness, and it carries risks of chemical burns and contact dermatitis [1]. Treatment of seborrheic keratosis requires medically evidence-based procedures [5,12].
Wood vinegar is a liquid made by cooling the smoke produced when charcoal is burned. It is composed of approximately 90% water and the remainder organic compounds.
Please do not attempt to remove seborrheic keratosis yourself — consult a physician instead.
✅ Seborrheic keratosis can occur in younger individuals as well [3,12]. Onset in people in their 20s and 30s has been reported in approximately 5–10% of cases, and the risk is higher when there is a family history or frequent UV exposure [3,8]. Both genetic predisposition and environmental factors are involved in its development [3].
In younger people, genetic factors are considered to play a larger role, and lesions tend to develop particularly around the neck, temples, and abdomen.
🏥 For Seborrheic Keratosis Treatment in Tokyo, Consult IC Clinic
Seborrheic keratosis is a skin condition also known as “age warts.” Because it is not a viral wart, over-the-counter wart products and herbal medicines are unlikely to be effective.
⚠️ If left untreated, it may progress and enlarge, so please seek medical attention promptly.
🌟 Features of IC Clinic:
- 👨⚕️ Experienced specialist physicians on staff
- 💰 Insurance-covered treatments available
- 🕐 Open on weekends and public holidays
- 📍 Conveniently located near the station
- 😊 A welcoming environment for patients of all ages and backgrounds
No matter what your concern, we will discuss treatment options with you individually and suggest the most suitable approach. If you are troubled by warts in any way, please do not hesitate to contact IC Clinic.
📚 References
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- Hafner C, Vogt T. Seborrheic keratoses: review of the literature and experience in daily practice. Dermatol Pract Concept. 2016;6(4):47-52.
- Yeatman JM, Kilkenny M, Marks R. The prevalence of seborrhoeic keratoses in an Australian population: does exposure to sunlight play a part in their frequency? Br J Dermatol. 1997;137(3):411-414.
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- Harii K, Hashimoto K, eds. NEW Dermatology, 3rd Edition. Nakayama Shoten, 2018.
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- Braun RP, Rabinovitz HS, Oliviero M, et al. Dermoscopy of pigmented skin lesions. J Am Acad Dermatol. 2005;52(1):109-121.
- Kittler H, Pehamberger H, Wolff K, et al. Diagnostic accuracy of dermoscopy. Lancet Oncol. 2002;3(3):159-165.
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- Shumack S, Gebauer K, Quirk C, et al. Photodynamic therapy for seborrheic keratoses: a randomized, vehicle-controlled study. Dermatol Surg. 2020;46(11):1429-1434.
- Del Rosso JQ, Kircik LH. Seborrheic keratoses: a review of clinical features and therapeutic approaches. J Clin Aesthet Dermatol. 2017;10(3):16-25.
- Baumann L, Weisberg E. Cosmetic Dermatology: Principles and Practice, 2nd Edition. McGraw-Hill Education, 2009.
- Zalaudek I, Argenziano G, Leinweber B, et al. Dermoscopy of seborrheic keratoses: a morphological study. Arch Dermatol. 2005;141(10):1267-1270.
- Japanese Society of Dermatologic Surgery, ed. Textbook of Dermatologic Surgery. Nankodo, 2019.
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