Why do older people get barnacles on their skin?

Over 83 million adults in the U.S. will be 65 or older by 2050, and many will notice common skin changes, including the development of non-cancerous skin growths known as seborrheic keratoses. These growths, often humorously nicknamed "barnacles of aging," are a normal part of the aging process and raise the question: why do older people get barnacles on their skin?

Quick Summary

Seborrheic keratoses, the actual term for skin "barnacles," are common, non-cancerous growths that appear more frequently with age due to a combination of genetic predisposition, slower skin cell turnover, and potentially sun exposure.

Key Points

• Seborrheic Keratoses (SKs) are Benign: These skin growths, often called "skin barnacles," are non-cancerous and harmless, primarily appearing as a normal part of the aging process.

• Causes are Multifactorial: A combination of genetic factors, the natural slowdown of skin cell turnover, and sun exposure all contribute to their development, especially in people over 50.

• Distinctive "Stuck-On" Appearance: SKs often have a waxy, scaly, or wart-like texture and look as though they've been pasted onto the skin, distinguishing them from other growths.

• Know the Difference from Skin Cancer: Although benign, SKs can sometimes resemble more serious growths like melanoma. Any new or changing skin lesion should be evaluated by a dermatologist for a definitive diagnosis.

• Removal is an Option: If a growth is bothersome, irritated, or a cosmetic concern, a dermatologist can remove it using methods like cryotherapy (freezing), electrocautery, or laser therapy.

• Not Contagious or Preventable: You cannot catch SKs from another person, nor can you completely prevent their development due to their strong genetic link. Regular skin monitoring is key.

• Rare Sign of Internal Malignancy: A sudden, explosive appearance of numerous SKs, known as the Leser-Trélat sign, is a rare phenomenon that may indicate an underlying internal cancer.

What Exactly Are Seborrheic Keratoses?

Seborrheic keratoses (SKs) are benign, non-cancerous skin growths that are extremely common in adults, especially those over the age of 50. They are often described as having a waxy, pasted-on, or "stuck-on" appearance, with a slightly raised and scaly surface. While they are not harmful, their appearance can be a cosmetic concern for some people. They can be tan, brown, or black and can occur almost anywhere on the body, though they are most frequently found on the face, chest, shoulders, and back.

The Science Behind the 'Barnacles of Aging'

The development of seborrheic keratoses is not caused by poor hygiene or any serious underlying disease. Instead, it is a complex process linked to several factors that commonly affect the body as it ages.

1. Genetic Predisposition

Genetics play a significant role in who develops seborrheic keratoses and how many they may have. If you have family members with numerous SKs, your own risk is considerably higher. Studies have identified specific gene mutations, such as those affecting the FGF and PIK3CA pathways, that are linked to the condition. This inherited tendency is one of the strongest predictors of whether or not you will develop these growths.

2. Slowed Cell Turnover

As the skin ages, the process of cell turnover—where old, dead skin cells are shed to reveal fresh ones—naturally slows down. This deceleration leads to an accumulation of keratinocytes, the cells responsible for producing keratin, the main structural protein of skin. This buildup of keratinocytes causes the thickened, raised appearance of seborrheic keratoses.

3. Sun Exposure

While not the sole cause, prolonged and chronic exposure to ultraviolet (UV) radiation from the sun is a known risk factor. UV light can cause DNA damage to skin cells, contributing to abnormal cell growth that can manifest as seborrheic keratoses. This may explain why SKs are so common on sun-exposed areas like the face, neck, and back.

4. Hormonal Changes

Hormonal shifts, particularly during significant life stages such as pregnancy or menopause, can also influence the development of seborrheic keratoses. Hormone replacement therapy has also been associated with an increased incidence of these growths.

5. Chronic Skin Irritation

Repeated friction or irritation can promote the formation of SKs, especially in areas where skin rubs against clothing or jewelry. This is more common in older skin, which tends to be thinner and more sensitive.

Seborrheic Keratoses vs. Other Common Skin Growths

It is important to distinguish seborrheic keratoses from other skin conditions, some of which can be more serious. Always consult a dermatologist for a proper diagnosis of any new or changing skin growths.

Feature	Seborrheic Keratosis (SK)	Actinic Keratosis (AK)	Melanoma (Skin Cancer)
Appearance	Waxy, stuck-on, raised, can be scaly.	Flat or slightly raised, rough, scaly patch.	Irregular shape, asymmetrical, multi-colored.
Cause	Genetics, aging, sun exposure.	Primarily caused by chronic sun exposure.	UV exposure causing DNA damage leading to uncontrolled cell growth.
Benign/Malignant	Benign (non-cancerous).	Pre-cancerous, can develop into skin cancer.	Malignant (cancerous).
Prevalence	Very common in adults over 50.	Common in middle-aged and older adults with fair skin.	Less common than AKs, but more serious.

Treatment and When to See a Dermatologist

While seborrheic keratoses are harmless, there are several reasons why you might want to consider removal. These include cosmetic concerns, irritation, or itching, especially if a growth is constantly rubbed by clothing. A dermatologist can typically diagnose an SK visually, but may perform a biopsy if there is any doubt about the diagnosis.

Removal Options

• Cryotherapy: Freezing the growth with liquid nitrogen. This is the most common method.
• Curettage: Scraping the growth off the skin after numbing the area. Often combined with electrocautery.
• Electrocautery: Burning the growth with a small electric current.
• Ablative Laser Therapy: Using a concentrated beam of light to destroy the growth.
• Topical Agents: Newer topical treatments, such as a 40% hydrogen peroxide solution, are now available for some cases, particularly on the face.

Warning Signs

It is important to see a dermatologist if you notice any suspicious changes in an SK or any other skin growth. This includes rapid growth, unexplained bleeding, changes in color or shape, or irregular borders. In very rare cases, the sudden eruption of numerous SKs can be a sign of internal malignancy, a condition known as the sign of Leser-Trélat.

How to Manage Skin Changes with Age

Managing skin changes as you age involves vigilance and proactive care. While you can't prevent seborrheic keratoses entirely, you can monitor your skin and take steps to address concerns.

• Regular Skin Checks: Get to know your skin and perform regular self-examinations. Document existing growths and look for any new ones or changes.
• Dermatologist Visits: Schedule annual skin exams with a dermatologist, especially if you have a family history of SKs or skin cancer.
• Sun Protection: Always protect your skin from UV radiation with sunscreen, hats, and protective clothing.
• Moisturize Regularly: Keeping your skin hydrated can help maintain its barrier function and overall health.

For more detailed information on common skin conditions and signs to watch for, the American Academy of Dermatology is an excellent resource, offering extensive patient education. American Academy of Dermatology website

Conclusion

While the appearance of seborrheic keratoses, or skin "barnacles," can be surprising, it is a very common and normal part of the aging process. The primary causes are a combination of genetics, natural skin aging, and sun exposure. These growths are almost always harmless, but it's crucial to distinguish them from more serious conditions. Regular monitoring and consulting with a dermatologist are key to managing these changes and ensuring your continued skin health. For most, these growths are merely a harmless, albeit sometimes bothersome, sign of a long life well-lived.

Frequently Asked Questions

What is the primary reason why older people get barnacles on their skin?

The primary reason older people get skin "barnacles," known medically as seborrheic keratoses, is due to aging and genetic factors. As skin ages, the natural process of cell shedding slows down, leading to the accumulation of skin cells that form these growths.

Are seborrheic keratoses the same as age spots?

No, seborrheic keratoses are different from age spots (lentigines). Age spots are flat areas of pigmentation caused by sun exposure, while seborrheic keratoses are raised, waxy, and often have a scaly texture.

Do seborrheic keratoses turn into cancer?

No, seborrheic keratoses are benign (non-cancerous) and do not turn into skin cancer. However, because they can sometimes resemble cancerous lesions, a dermatologist should examine any suspicious or changing skin growth to confirm the diagnosis.

Can I remove a seborrheic keratosis at home?

You should not attempt to remove a seborrheic keratosis at home. Doing so can lead to bleeding, infection, and scarring. A dermatologist can safely and effectively remove them using methods like cryotherapy (freezing), curettage (scraping), or electrocautery (burning).

If my parent has many seborrheic keratoses, does that mean I will get them too?

Having a family history of seborrheic keratoses is a strong risk factor, so it is likely you have a genetic predisposition to developing them as you get older. However, the number and location of the growths can vary widely.

Can sun exposure make skin barnacles worse?

While not the direct cause, chronic sun exposure is considered a risk factor for developing seborrheic keratoses and may increase their occurrence. Sunscreen and protective clothing can help protect against UV damage.

Should I be concerned if I suddenly develop many skin barnacles?

A sudden, widespread outbreak of numerous seborrheic keratoses is very rare and warrants a visit to a dermatologist. This could be a sign of an underlying medical condition, though it is important to remember that most cases of SK are a benign result of aging.

Are seborrheic keratoses itchy or painful?

Typically, seborrheic keratoses are painless and asymptomatic. However, if they are located in areas of high friction, like where clothing rubs, they can become irritated, itchy, or even bleed.