The Common Habits That Can Cause Bumps Under The Arms + How To Deal

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October 7, 2022 — 12:01 PM

Have you ever had a red bump that’s so ambiguous you can’t tell if its a pimple, ingrown hair, or something else entirely? Playing dermatologist at home isn’t easy—especially when a mysterious bump occurs in an odd place. One prime example: Armpit pimples.  

If you’ve never spotted a red bump under your arm, consider yourself lucky. These pesky bumps can be difficult to name and even more challenging to work around with a razor. Luckily, we asked derms for the 101 on armpit pimples so you can be bump-free stat. 

A true pimple on the armpit is like any other breakout—it’s made up of dead skin cells, oil, and bacteria clumping together in a sticky glob, clogging the pore. This, alongside some inflammation, will result in a red, angry pimple. 

While zits like these can certainly appear under the arms (and anywhere else you have pores), there’s a plethora of other bumps that are more likely taking up space in your armpit. A few of these include: 

Folliculitis: “The most common cause of acne-like bumps in the underarm area is folliculitis, which is an inflammation and sometimes infection around the hair follicles,” board-certified dermatologist Hadley King, M.D. tells mbg. This can present as small red bumps or larger nodules.  Dermatitis: “Dermatitis, which may result from irritation or skin allergies, can occur in the underarm and may appear as red, flaky patches or associated with red bumps,” board-certified dermatologist Marisa Garshick, M.D., FAAD explains.  Hidradenitis suppurativa (AKA acne inversa): “This is a chronic skin condition characterized by inflamed and swollen bumps and nodules that are typically painful and can drain fluid or pus,” King says. “The underlying mechanism is believed to involve a dysfunction of apocrine sweat glands and genetics play a significant role,” she explains. 

Hair removal: “Waxing and shaving can also trigger pimple-like bumps because the sensitive skin in this area is easily irritated and inflamed after hair removal,” King says.  Pore-clogging deodorant: If you’re experiencing underarm pimples after switching your deodorant, it’s probably the new product. “Underarm care may contribute to red bumps which may be traditional pimples depending on if the products used in the underarm cause clogged pores,” Garshick says.  Fragrance: No matter the source of the fragrance (natural, synthetic, a blend of both), some people are simply sensitive to the addition. “Fragrance is a common cause of dermatitis, and I recommend choosing a fragrance-free deodorant and antiperspirant whenever possible,” board-certified dermatologist Rebecca Marcus, M.D., FAAD explains. If you can handle fragranced options, feel free to keep using them. But if you find that you're breaking out, consider switching for unscented options. Sweat build-up: While sweating under your arms is pretty much unavoidable, you can use an antiperspirant (yes, antiperspirant is different from deodorant), if you believe the sweat is causing your underarm breakouts, Garshick says. We believe that natural, aluminum- and baking soda-free deodorants are the best options, but we also know that everybody's needs are different. If you find they don't work for you, then antiperspirant may be the way to go.

Wear loose clothing to avoid excess chafing Opt for a natural deodorant with antibacterial properties  Exfoliate before shaving Change your razor blade frequently 

If you already have an armpit pimple, there are a few expert-approved methods of treating it. While some face products may work as well, you should be mindful that you’re dealing with very different skin.

“The skin in the underarm is thin and because it is a skin fold, the skin rubs against itself and forms an area of occlusion, which can lead to irritation and friction,” Garshick says. Here, a few safe treatment options:

“An OTC [over-the-counter] topical spot treatment containing salicylic acid may be helpful,” Marcus suggests. Saliciylic acid is in a class of exfiliatior called BHAs or beta-hydroxy acids. Salicylic acid is particularly beneficial for acne-prone skin, due to its ability to break through oil and dead skin. Plus, it’s antibacterial. 

If you’re on the hunt for a grade-A choice, this First Aid Beauty Fab Pharma BHA Acne Spot Treatment Gel is a winner. While it will work wonders for the underarm area, you can keep it on hand for breakouts that pop up anywhere. 

“If ingrown hairs are the problem, the most definitive solution is getting rid of the hair,” King says. Laser hair removal is a great option for those prone to ingrowns, especially if its causing you discomfort or pain. 

It is important to note that laser hair removal is a pricey procedure, and it’s not a realistic option for everyone. But don’t worry, there’s plenty more budget-friendly products out there to help prevent and treat these bumps—here’s a few to get you started. 

“Before treating an armpit pimple, it's important to confirm that it is, in fact, a pimple, and not something else,” King says. One person who will know the answer to this tricky question: Your derm. 

Especially if you’re prone to breakouts outside of the underarms as well—whether it be on the face, back, neck, chest, etc.—then a prescription-grade product may work better than OTC options. 

If you frequent the clean beauty space, you may have heard of an “armpit detox.” Some people believe that the transitional stage of switching from an antiperspirant to a natural deodorant will cause the skin to “detox,” essentially purging all impurities. This tends to include an increase in sweat and odor. To be frank, there’s no research to back up this claim. 

However if you have recently switched to a natural deodorant, then you will most likely experience an increase in sweat given the lack of aluminum—the ingredient that blocks the sweat from coming out your pores. This increase in sweat can lead to more armpit pimples, Garshick explains, but only for some individuals.

If you want to use a natural deodorant but fear the increased sweat, just know it varies for everyone and it might not be a problem for you. If it is, you can always do a quick pit-wash midday if you’re worried about sweat buildup.