What Is Armpit Rash?

An armpit rash can be uncomfortable or even painful. Often, the cause is mysterious, but you can treat the conditions at home. Sometimes, however, an armpit rash is severe enough to require a trip to the doctor.

Learn symptoms of an armpit rash, what causes it, how it’s diagnosed, and treatment options.

A rash can develop in the armpits themselves or on the skin around the underarm area. It may appear red or darker than your natural skin tone, be raised or flat, or have pimple-like bumps. It can be wet or dry, and it may ooze fluids. It sometimes is itchy, too.

The armpits are susceptible to rash because they contain apocrine sweat glands, a type of sweat gland that produces an odor. Sweat and oil can get trapped in the skin, causing a heat rash.

There are many potential causes of armpit rash.

Friction Dermatitis

Friction dermatitis is a common rash. The friction created by skin rubbing on skin or clothing, also called chafing, can cause irritation.

Heat and excess sweating can contribute to chafing. Shaving also makes your underarms more vulnerable to damage from rubbing because it removes skin, adds Kathryn Durham, MD, an American Academy of Dermatology certified dermatologist with U.S. Dermatology Partners in Fort Worth, Texas.

Contact Dermatitis

There are two types of contact dermatitis: irritant contact dermatitis and allergic contact dermatitis.

Irritant contact dermatitis occurs when an ingredient or element of a product — such as cleansers, deodorants, or even clothing — disrupts the skin barrier, Dr. Farnsworth says.

Meanwhile, allergic contact dermatitis takes place when your immune system reacts to an ingredient, leading to a rash.

It can be tough to distinguish between the two types of contact dermatitis, as they can look the same. The culprits, such as fragrance or preservative, also are often the same, Farnsworth says.

Fungal Infection

Excess moisture from sweat encourages an overgrowth of yeast called Candida albicans, leading to a yeast infection.

“Yeast infections are often bright red, with bright bumps and pustules at the periphery, and often have a pungent, ‘cheesy’ smell,” Farnsworth says.

Ringworm is another fungal infection, caused by the fungi Trichophyton, Microsporum, or Epidermophyton. It can spread by skin-to-skin contact or by sharing things that touch your skin, like a towel.

Hidradenitis Suppurativa

Hidradenitis suppurativa is a skin condition that features painful lumps in your skin. The lumps resemble pimples and acne cysts and often appear in the armpits, inner thighs, or groin.

Hidradenitis suppurativa is more common in Black people compared with those of other races and affects women more often than men.

Folliculitis

Shaving sets the stage for folliculitis, a condition where bacteria enter hair follicles, causing them to become infected and inflamed, Dr. Durham says. Folliculitis appears as red or white pimple-like bumps; some are filled with pus.

Anyone can develop folliculitis, but it can be more common in people who are overweight or have obesity or type 2 diabetes. Sweating without showering or changing clothes, or spending time in hot tubs or saunas, also encourages folliculitis.

Atopic Dermatitis (Eczema)

This inflammatory skin condition — which can be genetic — can also show up in the armpits. Your skin may appear dry and red and feel itchy.

“Eczema loves skin folds, and armpits are one spot we might see it,” Durham says.

Inverse Psoriasis

A specific type of psoriasis, this condition leads to a painful rash in skin folds such as under your arms, which see a lot of friction, Durham says.

Anyone can get inverse psoriasis. Factors that may make you more susceptible include:

Alcohol use
Smoking
Stress
Obesity
Genetics
Vitamin D deficiency

Some Cancers

Armpit rash is a fairly rare symptom of some cancers, but there are links.

Extramammary Paget’s disease, a rare skin condition that may be associated with cancer, can show up as a persistent red, scaly, or itchy rash in the armpit.

While also rare, red raised bumps in the armpit that don’t resolve may be a sign of cutaneous lymphoma (lymphoma of the skin), particularly in males, Black adults, and people ages 50 and older.

Inflammatory breast cancer can cause swelling of the lymph nodes, small glands that help your body fight off infections, in your armpits that looks like a rash. This cancer is rare but aggressive.

Many underarm rashes are harmless, though often uncomfortable. Many causes of underarm rash do not need a doctor’s diagnosis, and you can treat them at home. These include instances where you’ve identified the cause, such as chafing or allergies.

Durham says that you should contact your healthcare provider if your symptoms include:

Painful bumps
Infection
Fever
New odor under your arm
General sick feeling

A dermatologist is an expert in all things skin, but your primary care provider can also diagnose an underarm rash.

For diagnosis, your provider will talk to you about your medical history and symptoms, conduct a visual examination of your rash, and may opt to do additional testing, such as a patch test, blood test, or biopsy.

You can treat many armpit rashes at home. Farnsworth recommends trying these measures before seeking other options:

Apply skin-healing ointment. Diaper rash ointment that contains zinc oxide helps treat and protect delicate underarm skin from irritation.
Petroleum jelly is another good product to apply to your underarms, as it helps soothe skin, Durham says.
Avoid skin-irritating ingredients. Check the ingredient label of any skin-care product that comes in contact with your underarms, including deodorants and antiperspirants, body wash, lotion, and even shampoo. Quit using any products that include fragrances and propylene glycol, which can be common culprits of underarm rash.

If these measures don’t help or your rash worsens, see your primary care provider or a board-certified dermatologist, Farnsworth says. They can diagnose a rash or underlying skin condition and prescribe medications, such as topical or oral antibiotics or anti-yeast or anti-inflammatory agents, he says.

You can do things in and out of the shower to care for your underarm skin and help prevent rashes.

First, wash with an antibacterial soap and gently exfoliate with a body brush, Durham says.

“Use the brush one to three times per week, depending on sweat and activity level,” she says. “It reduces bacteria and gets all of the products off to give skin a fresh start when we apply deodorant or antiperspirant.”

Other ways you can prevent armpit rashes include:

Wear breathable clothing.
Change out of sweaty clothes.
Wash sweat off your skin promptly.

Some rashes can cause complications, depending on the underlying cause.

For example, hidradenitis suppurativa may require surgery to drain a pus-filled bump.

An armpit rash can be serious if you have hidradenitis suppurativa, Farnsworth says. The lumps can develop abscesses or pus pockets, leading to scarring or pus-filled tunnels forming under the skin. Over time, scars that form in the armpit can impair your arm’s range of motion, and the condition can be painful.

Meanwhile, a folliculitis infection, which is usually mild, can spread to nearby areas or cause a scar if left untreated.

In other cases, underlying causes of an armpit rash, such as syphilis, can lead to complications such as organ damage if they are not diagnosed and treated.

Underarms are vulnerable to rash because they are a dark, moist environment that rubs against skin and clothing.
Most armpit rashes are mild and can be treated at home.
If you have an armpit rash, avoid irritants that touch the underarms.
If left untreated, underlying causes of an armpit rash can lead to serious complications.
Contact your healthcare provider if simple measures don’t improve the rash and you experience additional symptoms, such as a fever or fatigue.

Menu