What’s Causing Your Dark Underarms? Skin Conditions to Know

‍Skin discoloration under the arms is a relatively common condition. Known as acanthosis nigricans (AN), it typically occurs in areas where the skin folds, like the groin, elbows, knees, or—as we’re talking about here—the armpits.

AN patches usually appear gradually. The discoloration might be the only sign, or the skin might also become thicker. It can also be accompanied by itching and, rarely, an odor. In most cases, the condition is harmless. But it can sometimes be an outward sign of other things going on inside the body.

Dark Underarms Causes

Dark skin patches occur when pigmentation cells, known as melanocytes, increase. Underarm hyperpigmentation can have many root causes, including:

• Being overweight: This is the most common reason and is usually due to insulin resistance. 
• Type 2 diabetes: High blood sugar can cause AN.
• Hormone-related conditions: Like Cushing’s syndrome, an underactive thyroid, or polycystic ovary syndrome.
• Certain medications: Including the contraceptive pill and steroids.
• Cancer: Rarely, AN can be an outward symptom of cancer of the stomach, colon, or liver.
• Genetic: The condition is also known to run in families.

However, there are some instances when a person with no other underlying conditions can develop AN. This is generally seen in darker skin tones.

When to See a Dermatologist for Dark Armpits

It can be quite alarming to notice darker patches developing under your arms or, indeed, any other area of the body. While most are harmless, it’s important to get any changes checked out by a professional—the sooner you get a diagnosis, the quicker a treatment plan can be actioned. If, for instance, it’s because of insulin resistance or high blood sugar, then this also has other health implications over and above being aesthetic.

A dermatologist will take a detailed history, which includes when you noticed the changes, if you have any relatives with the condition, and any medications you take. Although they can diagnose AN simply by looking at the skin, you’ll likely undergo some other tests, like a blood analysis, as well. This provides the clinician with valuable additional information to determine the cause.

Once the results are back, treatment can begin. As with all health issues, targeting the root of the problem is key. 

• If obesity is the issue, then losing weight is key. Being very overweight also increases the likelihood of insulin resistance, which you might also hear called “prediabetes”. Dietary changes and exercise are the best way to approach this. In some cases, weight loss drugs might be appropriate.
• Hormone syndromes will require the relevant treatment for the particular condition. Your dermatologist will most likely address this in conjunction with other medical professionals.
• Hyperpigmentation caused by medication may also require additional clinical input to reduce or change any drugs that are the root cause.
• Tumors or cancer will need the expertise of a relevant oncologist. When it occurs in conjunction with cancer, it’s known as malignant acanthosis nigricans.

A dermatologist has particular ways to target the appearance of AN. These include:

• Chemical peel: To help remove any thickened skin.
• Retinoids: Creams and/or pills containing this are one of the primary methods of treatment. It helps lighten and thin the skin, improving the appearance.
• Vitamin D-based creams: These help reduce the number of pigment-making cells.
• Dermabrasion: This removes the upper layers of skin, effectively resurfacing it, reducing any thickening and revealing the lighter skin below.
• Topical antibiotics and antibacterial soaps: To relieve any discomfort.
• Laser therapy: This targets the darker skin to reduce the thickness.

While most episodes of dark skin patches are harmless, it’s always worth getting them checked by a dermatologist. Underarm hyperpigmentation and skin discoloration usually fade when either the underlying cause is addressed or through targeted dermatological care.

The experts at Bayou City Dermatology can advise and treat accordingly. Head over to Services | Bayou City Dermatology to find out more and call today to book a consultation.