What Is the Medical Condition “Dirt Neck”? Plus, the Slang Explained

“Dirt neck” often refers to a darkening of the skin around the neck. There can be multiple causes for this darkening, but it’s most often caused by a condition called acanthosis nigricans (AN), which can also affect the skin on the armpits, fingers, and groin. The term “dirt neck” is also sometimes used as an insulting slang term. We spoke to double board-certified dermatologist Ellen Turner to learn more about acanthosis nigricans and how to treat it.

What is a dirt neck?

According to double board-certified dermatologist Ellen Turner, “dirt neck” refers to acanthosis nigricans, a condition that causes skin to get thicker and look darker. Acanthosis nigricans isn’t dangerous, but it can be a sign of an underlying condition like diabetes or PCOS, so if you notice it, talk to your doctor. “Dirt neck” is also sometimes used as derogatory slang.

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What does “dirt neck” mean in slang?

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In slang, “dirt neck” is almost always used as a derogatory insult. It’s often used as a general put-down. It might indicate that someone has a low social standing or that they’re unclean. It can also mean someone who spends a lot of time outside or in dirt jobs, like construction workers or other blue collar workers. And sometimes it just means people who participate in outdoor sports and activities that cause them to get—literally—a dirt neck.
- Rarely, “dirt neck” has been used as a racial slur against African-Americans.
Meet the wikiHow Expert

Ellen Turner is a Double Board-Certified Dermatologist based in Dallas, Texas. She's the founder of the Dermatology Office, which offers an array of dermatology services, including medical, cosmetic, surgical, and laser procedures.

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What is Acanthosis Nigricans?

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Acanthosis nigricans is a condition that causes skin to look dark and velvety. Dr. Turner says, “Acanthosis nigricans is a genetic condition appearing as velvety brownish or greyish patches or plaques on the neck or the axillary regions.”^{[1]
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Ellen Turner
Double Board-Certified Dermatologist

Expert Interview} The skin becomes thickened in areas where it creases, causing it to look darker. Acanthosis nigricans most commonly affects the neck, armpits, and groin, although the skin around the fingers, elbows, and knees may also be affected.^{[2]
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- Acanthosis nigricans itself is not harmful. However, it is sometimes a sign of an underlying condition, so talk to your doctor about it—especially if it appears suddenly.
- The skin affected by acanthosis nigricans often feels soft. It may be itchy and more prone to developing skin tags.^{[3]
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  National Health Service (UK)
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- Acanthosis nigricans is not caused by dirty skin. This condition can not be washed away, and scrubbing won’t lighten the skin.
- Acanthosis nigricans is not contagious—it can’t be passed to someone else.^{[4]
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Section 3 of 7:

Causes of Acanthosis Nigricans

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The exact cause of acanthosis nigricans is still being studied. Dr. Turner says that acanthosis nigricans “often occurs as a precursor for other genetic comorbidities such as diabetes mellitus Type II, obesity, [and] fatty liver to name a few.”^{[5]
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Ellen Turner
Double Board-Certified Dermatologist

Expert Interview} Genetics certainly play a role, as people with a family history of acanthosis nigricans are more likely to develop the condition. Having a darker skin tone may also increase the likelihood of developing acanthosis nigricans.^{[6]
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Cleveland Clinic
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Go to source} Additionally, some conditions and medications may be risk factors:
- Insulin resistance: Conditions like diabetes, prediabetes, polycystic ovarian syndrome (PCOS), and Cushing’s syndrome can make the body resistant to insulin. This might increase the chances of developing acanthosis nigricans.
- Drugs and supplements: If you take birth control pills, corticosteroids like prednisone, or high doses of niacin, you may be more likely to develop acanthosis nigricans.
- Cancer: Rarely, acanthosis nigricans can develop in patients who have certain cancers, like lymphoma and stomach or liver cancer.
- Obesity: People who are significantly overweight are at a higher risk of developing acanthosis nigricans.^{[7]
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It’s not caused by unclean skin, and the darkness can’t be washed away, no matter how much the person scrubs.^{[8]
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Cleveland Clinic
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Go to source} Additionally, it’s not caused by an increase in skin pigmentation—the skin looks darker because it’s thicker than the skin around it. That means traditional skin lightening treatments are typically not effective for treating acanthosis nigricans.

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How is Acanthosis Nigricans diagnosed?

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Your doctor may diagnose acanthosis nigricans after an examination. They’ll likely ask you about your family history of skin discoloration, and they’ll physically examine your skin.^{[9]
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Cleveland Clinic
Educational website from one of the world's leading hospitals

Go to source} Additionally, some doctors might do blood tests to check for or rule out underlying causes like diabetes.
- Your doctor might also take a skin biopsy if the cause of the skin darkening is inconclusive.
- If you have family members with acanthosis nigricans, you may want to take preventative measures. Dr. Turner says that eating a healthy diet high in fruits, vegetables, and fiber, as well as avoiding processed foods, can help prevent the condition from developing. Additionally, exercising 30-60 minutes at least 3-5 times per week can also “potentially ward off these other systemic issues before they arise.”^{[10]
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  Ellen Turner
  Double Board-Certified Dermatologist
  
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Treatment Options for Acanthosis Nigricans

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Acanthosis nigricans can fade over time. It may gradually improve once the underlying cause is properly managed. For instance, in patients with diabetes, the skin on their neck may gradually lighten once their insulin levels are stabilized.^{[11]
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National Health Service (UK)
Public healthcare system of the UK

Go to source} Or, in patients who are overweight, it may improve with diet and exercise.
- Similarly, if you’re taking a medication that causes this condition, it may improve once you stop taking that medicine or switch to another one.
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Dermatological treatments may also help improve acanthosis nigricans. Dr. Turner explains, “Topical treatments have been used for this condition to treat it, but are not generally effective in curing it, only controlling it once it has arisen. Exfoliative moisturizers such as glycolic acid or uric acid can be used. Retinoid acids have also been used but it must be managed carefully in order to avoid the concomitant irritation effect these may cause.”^{[12]
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Ellen Turner
Double Board-Certified Dermatologist

Expert Interview} These treatments are typically designed to help reduce the thickness of the skin—simply lightening the area may not work, since the condition isn’t caused by hyperpigmentation.^{[13]
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Cleveland Clinic
Educational website from one of the world's leading hospitals

Go to source} Talk to your dermatologist about treatments like:
- Laser therapy/dermabrasion
- Retinoids
- Antibiotics (if the acanthosis nigricans causes itching or an odor)
- Tretinoin^{[14]
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- Ammonium lactate
- Urea
- Salicylic acid

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Other Causes for Darkened Skin on the Neck

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Terra firma-forme dermatosis Terra firma forme is a fairly rare condition where dark-colored plaques form on the skin. These plaques look like dirt and often occur on the neck or chest, likely as a result of the accumulation of skin cells due to incomplete exfoliation (keratinization). It commonly appears in children.^{[15]
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- The dark areas can’t be removed by regular washing, but unlike acanathosis nigricans, this “dirt” can be wiped away with a cotton swab or tissue dipped in rubbing alcohol.
- The condition is often associated with dermatosis neglecta, where a dark, crusty scale appears on the skin in individuals with poor personal hygiene. However, dermatosis neglecta does wash away with regular soap and water, while terra firma-forme does not.
Hyperpigmentation (excessive pigment in the skin) can sometimes occur in the neck, causing it to look darker than the surrounding areas. This may occur due to skin damage or other trauma to the skin.^{[16]
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How do you remove dirt from your neck?

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Wash your neck with soap and water and gently exfoliate if it seems dirty. Sometimes, you can get a buildup of dirt on your neck as a result of not fully washing or exfoliating the area properly when you shower. Hair and body products can also create buildup on your skin. To remove it, use a textured sponge or loofah and your regular body soap to thoroughly clean your neck in small circular motions—but don’t scrub to the point that it’s uncomfortable.^{[17]
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American Academy of Dermatology
Professional organization made of over 20,000 certified dermatologists

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- If the dirt is still there, try swabbing it off with an alcohol wipe or a cotton ball dipped in rubbing alcohol. If that works, the dirt was likely a result of terra firma forme, or unshed skin cells. Continue washing as normal and wipe the area with alcohol as needed until the condition improves.^{[18]
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