Armpit Rash: 12 Possible Causes and How to Treat Them

Look, we’ve all been there—digging through our skincare stash trying to figure out why our armpits are giving us grief. One day everything’s normal, and the next? Your pits are red, itchy, flaky… maybe even kind of angry-looking. And no, you’re not imagining it.

If you’re dealing with an armpit rash, I totally get it. Sometimes that tender spot hidden under your shirt feels like some kind of personal rebellion against your daily routine—and truthfully, that’s what rashes can feel like. A little betrayal by your own body.

But here’s the good news: most armpit rashes are treatable, totally manageable, and rarely anything seriously worrying. Yep, even those pesky itchy armpit rashes that won’t quit can usually be handled at home with a few smart tweaks.

That said, sometimes a rash is just a rash—and other times, it’s telling you something important about your overall health. So in this guide, we’re going to break down the 12 most common causes of armpit rash, tell you how to tell them apart, and walk you through exactly what to do if you think you might have one.

What Causes Armpit Rash?

There’s no single answer here—it could be something as simple as sweat catching up with your morning jog, or as involved as a reaction to the last deodorant you tried on sale (cough, armpit rash from deodorant, cough). Let’s take a closer look at all the different reasons why your underarms might not be too happy with you right now.

Allergic Reaction To Deodorants

Let me guess—you switched deodorants last week and boom, a rash appeared? Yup, that one stings a little more than it should. Deodorants, especially fragranced or aluminum-heavy ones, are a common culprit for armpit rash from deodorant.

Here’s what’s going on: Your underarms are packed with nerve endings and sensitive skin. That means anything strong or irritating can send off alarm bells quickly. Ingredients like parabens, lanolin, or even essential oils might be the hidden villains here.

Symptoms:

• Redness and irritation
• Bumps or blisters
• Itching that seems to follow a pattern (like right after using a new product)
• Pus-filled spots (rare)

How To Fix An Armpit Rash From Deodorant

The first move? Ditch the suspect product ASAP. Switch to a hypoallergenic, aluminum-free deodorant—yes, they actually exist and work well. Brands like Native, Schmidt’s, or Almay have rashes their fans rave about without the chemical overload.

Then do this:

1. Clean the area gently with lukewarm water.
2. Pat dry; don’t rub.
3. Apply an over-the-counter hydrocortisone cream or calamine lotion to calm inflammation.
4. Don’t reapply your usual deodorant until the rash clears up (a few days).

Candida (Yeast Infection) Rash

Hmmmm another cause of itchy armpit rash you may not see coming? Yeast infections. That’s right—the same type that can affect skin folds elsewhere can also irritate your underarms, especially if you’re:

• Really sweaty
• In hot weather
• Wearing tight synthetic clothes
• Have diabetes or are immunocompromised

So what gives? Candida lives naturally on our skin, but when conditions get overly warm and moist, it multiplies… and starts causing problems. The fungal nature shows itself with these signs: Signs of candida rash include:

• Bright red, raised patches
• Pimple-like bumps around the edge (satellite lesions)
• A smell that’s… well, distinctly “cheesy”

Treating Candida Skin Infection

Oftentimes, an over-the-counter antifungal like clotrimazole does the trick. But if it lingers past a week—or gets worse—reach out to a doctor because prescription strength could be needed.

Also helpful for prevention? Change out of wet shirts quickly, opt for cotton tees, and maybe a shower after a sweaty gym session. Bonus points if you use a fan or open window during summer naps.

Heat Rash (Miliaria)

Even though we joke about “summer vibes” and breezy sundresses, heat does weird things to the body—especially your underarms if you work in a windowless office where A/C has definitely taken five.

This type of itchy armpit rash is technically called miliaria, or more plainly put—heat rash. It happens when your pores get clogged under layers of sweat, and suddenly bumpy red dots show up without warning.

Signs of Heat Rash

• Tiny, prickly bumps – think little goosebumps under your arms
• Redness
• Mild burning or stinging

Best Practice Tips

Instead of slathering on creams or lotions that might clog your pores further, go light. Take cool showers, wear breathable clothes, avoid harsh scrubbing. Let the skin cool down and air out. Trust me, your pits will thank you.

Cause	Solution
Overheating	Stay cool & hydrated
Clogged sweat glands	Switch to lighter anti-perspirants
Chemical irritation	Try unscented options

Eczema & Seborrheic Dermatitis

Eczema (also known as atopic dermatitis) can pop up almost anywhere—even your armpits. These flare-ups often look dry, red, and scaly, and they might itch like there’s no tomorrow.

Another form called seborrheic dermatitis typically shows up in oilier parts of the body, including your scalp and folds like the armpit. With this type, the skin tends to look greasy or flaky rather than dry. Both are lifelong conditions, but definitely manageable.

Home Care Steps

• Use fragrance-free soaps and shower gels
• Dry gently with patting—not rubbing
• Moisturize immediately after bathing while the skin is slightly damp

Folliculitis – Tiny Bumps That Look Like Acne

Ever shaved your armpits and later noticed little red bumps? Those aren’t pimples trying to crash the summer party—they’re folliculitis.

In short, tiny scratches during shaving can let bacteria sneak into hair follicles. Once that happens, you’ve got an infection of sorts, usually appearing as:

• Small, red bumps
• Pus-filled blisters
• Tenderness around the shaved area

Pro Shaving Tips

If you shave underarms, make sure your razor isn’t dull and change blades regularly. Also, only shave in one direction, not against the grain—and always moisturize after, without rubbing hard. Using a pre-shave oil can minimize breakouts too!

Intertrigo – Trapped Sweat and Friction

This isn’t technically a rash, but rather irritation resulting from two skin surfaces rubbing together continuously—usually occurs in folds like the armpits, groin, or underneath breasts.

When you sweat, which we all do, intertrigo loves hot and sticky environments. Combined with friction, it causes chafing, intense redness, and painful cracking of the skin.

Cause	Solution
Tight clothing	Wear loose, natural fiber fabrics
Prolonged sweating	Dry off often & consider powder
Skin rubbing together	Petroleum jelly or barrier ointments

I know what you’re thinking: “Why should I care so much about powders or clothing choices?”

Well, think of your underarms as sensitive zones. Like how the soles of your feet get sore easily, constant pressure leads to discomfort—and eventually irritation. The smallest changes make a difference.

Hidradenitis Suppurativa (HS)

Now this one’s a bit trickier—and less talked about. Hidradenitis suppurativa (HS) affects folks who maybe assumed their persistent armpit bumps were stubborn boils or zits.

HS creates painful, long-lasting lumps in sweat gland-rich areas like armpits, inner thighs, and groin. Despite its appearance, HS isn’t caused by bad hygiene, stress, or something you ate—it’s chronic inflammation of hair follicles that evolves over time.

What To Do

You definitely need a doctor to diagnose HS—it looks similar to severe folliculitis or boils, but comes back again and again. Often starts in late teens or early twenties, and tends to run in families. Left untreated, it can scar deeply and become quite disabling emotionally.

Early treatment might include lifestyle changes (like quitting smoking), antibiotics, or topical therapies. Later stages may require surgical intervention or specialized medicines prescribed by dermatologists.

Psoriasis – The Other Red Rash In The Fold

While psoriasis usually brings to mind thick plaques on elbows and knees, it can also affect the body’s crevices—including those tucked-away spaces like your armpits.

Inverse psoriasis presents differently from classic psoriasis—smooth, raw-looking red patches that don’t flake much. Since the area is already prone to rubbing and moisture, it reacts badly when psoriatic inflammation sets in.

Treating this varies depending on how extensive it is—if you notice mirrored plaque-like areas elsewhere, odds are it’s inverse psoriasis. A biopsy may be helpful if the doctor isn’t sure.

Serious Signs: Could It Be Cancer Or STD?

No, we’re not going to fearmonger—but certain conditions do cause concerning skin manifestations that shouldn’t be ignored. Rashes can reflect systemic illnesses, infections or rare immune responses—and now, we’ll cover two such possibilities:

Armpit Rash Cancer & Lymphoma Rash

While extremely rare, persistent armpit rashes that won’t heal and come with other issues—like swollen lymph nodes or generalized fatigue—could indicate possible lymphoma or cutaneous T-cell lymphoma.

In these cases, the skin lesions don’t get better despite antibiotics, OTC creams, or better hygiene habits. Instead, they may evolve, spread, or stay static for months.

According to Everyday Health, lymphomas typically manifest with painless nodules or erythematous plaques. These should prompt immediate dermatology referral.

Bottom line: Any stubborn rash lasting longer than two weeks with no response to home care merits a medical review. If swollen lumps accompany the rash, please go sooner—especially if they’re increasing in size.

STD-Related Rashes

In rare instances, secondary syphilis can present with a symmetric rash across the trunk and limbs—including armpits—and does not itch. And while a single lesion (chancre) from primary syphilis appears elsewhere, widespread symmetrical rash can be a key sign of infection spreading systemically.

Other systemic STIs like HIV may manifest with flu-like illness plus skin eruptions anywhere on the body as part of seroconversion reaction.

As detailed in several reviewed studies (like here), untreated syphilis can spread silently, compromising health over time. Early detection makes treatment 100% effective.

So yes—you can get an armpit rash from certain conditions involving sex—just remember that many STI-related rashes also affect your face, palms, or soles. Isolated pit eruptions are less commonly linked—but always worth talking through with healthcare providers who can run discreet tests.

Natural Help: Home Remedies for Gentle Rashes

If your rash seems pretty mild and consistent with things like irritation or contact dermatitis, consider trying some of these gentle home remedies:

• Oatmeal baths – grind half cup rolled oats and pour into bathwater to soothe irritated skin
• Aloe vera gel – cleansed and pure, works wonders on burning or inflamed spots
• Cold compresses – wrapped in soft cloth and pressed gently to inflamed areas several times a day
• Fragrance-free laundry detergent – since clothing rubbing against your pits might be triggering sensitivity

When Should You See a Doctor?

Yes, lots of armpit rashes can be managed at home. But sometimes what seems normal could actually signal a bigger issue. Here’s when it’s important to check with your doctor or a dermatologist:

• Persistent for over 2 weeks, especially without improvement
• Rapidly spreading or evolving
• Signs of infection (pus, yellow/green discharge, warmth)
• Accompanied by systemic symptoms like fever, chills, swollen glands
• Soreness that interferes with basic tasks like raising your arms

Embracing Your Body Again

Alright—we’ve covered a lot—but hopefully, none of this feels scary. Most of us will deal with an occasional itchy armpit rash, and nearly every one of them can be sorted out pretty easily. Understanding your body, your triggers, and treating issues quickly helps you stay confident—and rash-free!

And whatever you do, don’t hesitate to advocate for yourself. Whether it’s going to Urgent Care or admitting you’ve tried every product on Amazon without knowing what works—you deserve peace of mind. Start by dropping your assumption that rashes are embarrassing. They’re actually a form of communication.

Your skin just wants clarity—and better hygiene helps, sure—but mostly, it just wants to breathe, stay clean, and be respected.

Go easy on yourself. If you’ve got more questions about your armpit rash, share your experience down below or send us a message. We’ve all been there—and now we’re here to help.