Dark underarms are often a symptom of acanthosis nigricans. Typically this skin disorder occurs in people with an underlying medical condition, such as diabetes or obesity.
The dark color itself is generally not a cause of concern. Some people, however, do not like dark underarms for cosmetic reasons, and may want to try using the following methods to treat them:
- applying topical creams
- having laser therapy
- using natural remedies, such as lemon juice or sea cucumber extract
Acanthosis nigricans (AN) may also contribute to skin thickening or darkening in other areas of the body, such as the neck and groin. AN affects 7 to 74 percent of people, with prevalence varying by race, sex, and body weight.
What are the causes?
Dark areas of skin can occur when skin pigment cells multiply more rapidly than usual.
This may be attributed to frequent removal of hair.
Regular shaving of the underarms can cause excessive pigment cell production.
As well, the following factors can increase AN ‘s likelihood:
- Insulin resistance: The majority of people with this condition are insulin resistant. Being insulin resistant means that the body has become less sensitive to the effects of insulin. Insulin resistance can eventually lead to type 2 diabetes.
- Obesity: People who are obese are more likely to notice dark skin in their underarms and other areas of their body. According to research, more than half of adults who weigh over 200 percent of their ideal body weight have AN.
- Hormonal disorders: People with an underactive thyroid, polycystic ovary syndrome (PCOS), or other hormonal disorders are more likely to have AN than others.
- Genetics: AN appears to run in families, which means that it is likely to have a genetic cause.
- Race: AN is most common in Native Americans, followed by African-Americans, Hispanics, and Caucasians.
- Medication use: Some medications, including high-dose niacin, birth control pills, and corticosteroids, may cause AN.
- Cancer: In rare cases, AN can occur because a cancerous tumor is growing in the stomach, liver, or another internal organ. This form of AN is called malignant acanthosis nigricans.
Everyone in the underarms or other areas of the body is at risk of developing AN. Some people are more likely to get this skin condition though than others.
Risk factors for dark underarms include:
- having a close family member with the condition
- having darker skin
- being obese
- having diabetes or insulin resistance
- shaving or plucking under the arms too often
- having a hormone condition
- taking certain medications
- having cancer of the stomach, liver, or colon
Treatment for AN
Treatment typically involves administering the underlying AN cause. Treatment options can include, depending on the cause:
- taking medication to keep diabetes under control
- losing weight if overweight
- managing hormonal disorders with medicines and lifestyle changes
- switching to another drug that does not cause AN, where possible
- having surgery to remove cancerous tumors
If there is no underlying cause for AN then treatment is not necessary.
Tips to get rid of dark underarms
People with cosmetic concerns may use several methods to try to lighten the skin including:
Moisturizing the underarms
Shaving or plucking underarm hair too often may cause dark underarms, so moisturizing can be helpful to reduce underarm irritation.
Before shaving, always use a soap or shaving cream, and pick one for sensitive skin.
Following shaving, add a natural and unscented moisturizing lotion to the area to reduce discomfort and avoid skin changes.
Applying a natural remedy
Some people claim natural treatments can make dark skin lighter. Scientific research to support these claims is limited, if any.
For dark underarms, common natural remedies include:
- curcumin, which is a pigment in turmeric
- lemon juice
- milk thistle
- sea cucumber extract
Some of these home remedies may cause side effects. For example, lemon juice can dry out or irritate the skin.
Before using any home remedies for dark underarms it is best to speak with a doctor or dermatologist.
Topical creams and antibiotics
There are prescription creams, ointments, and gels to lighten the skin under the arms. These products include:
- retinoid creams to thin and lighten the skin
- hydroquinone cream to lighten the color of the skin
- chemical peels containing trichloroacetic acid (TCA) to remove damaged skin cells
- calcipotriene (Dovonex), a vitamin D-based cream to reduce pigmentation
- topical antibiotics or antibacterial soaps to minimize discomfort
Many dermatologists recommend topical creams and antibiotics as they can reduce skin discolouration and enhance the underarm appearance. It should be remembered, however, that the manufacturers of these goods did not explicitly develop them for AN.
Retinoid drugs can cause a variety of side effects and are not suitable for pregnant women. Before using these drugs, people considering AN should discuss the benefits and disadvantages with their dermatologist.
Laser therapy may reduce the thickness of the skin, which often happens along with skin darkening. Reducing skin thickness may make it appear lighter in colour.
Laser therapy can also improve hair growth and therefore reduce the need for shaving.
Preventing AN isn’t always possible, but some ways to reduce the risk of developing dark underarms include:
- maintaining a healthy weight
- talking to a doctor about switching to another medicine that does not cause AN, if relevant
- using shaving foam and moisturizing lotion on the underarms
- managing medical conditions that may contribute to AN development
AN generally is not a cause of concern. People with dark underarms, however, should see their doctor as skin darkening may indicate an underlying medical condition requiring treatment.
Treatment of the underlying condition often resolves symptoms and makes the skin lighter. If that doesn’t function, or if an underlying condition does not cause AN, a doctor or dermatologist may prescribe home remedies, medications, and therapies.