Dark underarms are often a symptom of acanthosis nigricans. This skin disorder typically occurs in people who have an underlying medical condition, such as diabetes or obesity.
The dark color itself is not usually a cause for concern. However, some people dislike having dark underarms for cosmetic reasons and may wish 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 cause thickening of the skin or darkening in other areas of the body, such as the neck and groin. AN affects between 7 and 74 percent of people, with the prevalence varying according to age, race, and body weight.
Dark areas of skin may occur when pigment cells in the skin multiply faster than usual.
This can occur as a result of repeated hair removal.
Regularly shaving the underarms can lead to excessive production of pigment cells.
The following factors can also increase the likelihood of AN:
- 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 is at risk of developing AN in the underarms or other areas of the body. However, some people are more likely than others to get this skin condition.
Risk factors for dark underarms include:
Treatment typically involves managing the underlying cause of AN. Depending on the cause, treatment options may include:
- 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.
People with cosmetic concerns can attempt to lighten the skin using several methods, including:
Moisturizing the underarms
Shaving or plucking underarm hair too often may cause dark underarms, so moisturizing can be helpful to reduce underarm irritation.
Always use a soap or shaving foam before shaving, and choose one for sensitive skin.
Apply a natural and unscented moisturizing lotion to the area after shaving to reduce irritation and prevent changes in the skin.
Applying a natural remedy
Some people claim that natural treatments can lighten dark skin. There is little, if any, scientific research to support these claims.
Popular natural remedies for dark underarms include:
- curcumin, which is a pigment in turmeric
- lemon juice
- milk thistle
- sea cucumber extract
Some of these home remedies may cause side effects. Lemon juice, for example, may dry out or irritate the skin.
It is best to talk to a doctor or dermatologist before using any home remedies for dark underarms.
Topical creams and antibiotics
Prescription creams, ointments, and gels are available 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 discoloration and improve the appearance of the underarms. However, it is worth noting that the manufacturers of these products did not design them specifically for AN.
Retinoid drugs can cause several side effects and are not suitable for pregnant women. People considering these medications for AN should discuss the advantages and disadvantages with their dermatologist before using them.
Laser therapy can reduce the skin thickness that often occurs alongside skin darkening. Reducing the thickness of the skin may make it appear lighter in color.
Laser therapy may also decrease hair growth and subsequently reduce the need to shave.
It is not always possible to prevent AN, 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 is not generally a cause for concern. However, people with dark underarms should see their doctor as skin darkening may indicate an underlying medical condition that requires attention.
Treating the underlying condition often resolves the symptoms and lightens the skin. If that does not work, or if an underlying condition is not causing AN, a doctor or dermatologist can recommend home remedies, medications, and therapies.