Underarm Rashes

Rash or infection on womans underarm.
Underarm rashes are typically caused by heat, friction or contact with allergens.
© iStockphoto.com/Robert Byron

Getting rashes under your arms can really be the pits, but while these rashes have a variety of causes, most aren't cause for alarm. An armpit is a dark, moist place that's a perfect breeding ground for bacteria and other microbes. Some of these bacteria produce odor as they grow, which is why many people use deodorant, but sometimes both the microbes and that deodorant can work against you -- the result is a rash.

An underarm rash isn't usually the result of poor hygiene -- in fact, a rash may occur as the result of a product you use to stay clean and odor-free. Perfumes, deodorants and drying soaps can all cause an allergic reaction, and even shaving under your arms can cause a rash [source: Mayo Clinic].


Rashes come in all shapes and sizes -- some appear as raised patches of blotchy dry skin, others as itchy red bumps or pimples. Some rashes hurt, others itch like crazy, and others may cause no pain or itching at all [source: Mayo Clinic]. But given how sensitive your underarm area is, even when a rash is painless, you'll want to get it cleared up as soon as possible.

If you spot a breakout, don't be rash -- step back and use the following information to figure out the cause and treat the problem. But don't hesitate to visit your doctor if the problem persists or if the rash is accompanied by other symptoms.

Keep reading to learn about the causes of underarm rashes.


Underarm Rash Causes

There are several factors that can cause your underarms to break out in a rash. Three of the most common culprits are heat, friction and contact with allergens.

Heat rash occurs when your sweat ducts are blocked and perspiration builds up beneath the skin, causing a bumpy and sometimes painful inflammation. It's not always clear why sweat ducts become blocked, but certain factors can contribute to it, including bacteria, tight-fitting clothing, medications and certain fabrics [source: Mayo Clinic].


Friction can also cause skin irritation in the underarms -- this is an area of the body where skin continually rubs against fabric or other skin. Friction, combined with heat and moisture, breaks down the epidermis and can cause inflammation. While this may be uncomfortable enough on its own, it's often complicated when bacteria or fungus colonize among the broken skin and infect it [source: Selden]. One specific type of infection that may develop in this manner is candidiasis, or a yeast infection [source: Ripper].

Contact dermatitis is a very common cause of skin irritation on the body, including the underarms. Contact dermatitis works just like it sounds -- if something touches your skin that irritates it or causes a reaction, a rash can develop. When this occurs in the underarms, deodorant or antiperspirant is often the culprit. However, if the rash is bumpy or blistering, an allergy may be responsible [source: Mayo Clinic].

Keep reading to learn how to treat and prevent underarm rashes.


Preventing Underarm Rashes

To prevent underarm rashes from developing, it's important to understand what causes them in the first place. One way to avoid heat rash is to simply not go outside in hot, humid weather. If you have to be outside, try not to overexert yourself, and wear loose-fitting clothing made of porous fabric. Also, don't use powders, creams or ointments on your skin -- they can clog pores and interfere with perspiration [source: Mayo Clinic]. The preventive measures for friction rashes are the same as for heat rash -- keep your underarms dry and wear light, loose-fitting clothing [source: Selden].

If you suspect that skin care products or household chemicals are causing your rash, the best way to avoid contact dermatitis is to identify the offending product and discontinue its use. Determining the culprit may require some trial and error, but it's best to start with your deodorant. Other items that may cause underarm rash include laundry detergent, soap, shampoo and lotions. If your symptoms don't improve, or if you're unable to identify what's causing your rash, see your physician -- he or she can test for a specific allergy [source: Mayo Clinic].


Once you've succeeded in identifying and eliminating the cause of your underarm rash, it's time to focus your attention on treating its symptoms. Keep reading to learn more.

Underarm Rash Treatments

Many rashes disappear on their own in a few weeks, but a few weeks can seem like an eternity if your rash is itchy or painful. However, there are ways to get immediate relief from an underarm rash.

If your rash isn't severe or infected, you probably just need to soothe irritation at the rash site. Calamine lotion is the most common topical treatment for rashes, but you can also apply a hydrocortisone cream or take an antihistamine. Pampering yourself by soaking in an oatmeal bath is a great way to soothe skin and relieve itching, and if your rash is painful, taking ibuprofen or aspirin should ease pain and inflammation. While you have the rash, take extra care to keep your underarms cool and dry by wearing loose-fitting clothing and applying absorbent powder [source: WebMD].


While these home remedies should help relieve your symptoms and clear up your rash, see a doctor if the rash persists or if your symptoms worsen. In cases of severe inflammation, topical steroids may be necessary to ease the outbreak. Should an infection complicate the condition, you'll need an antibiotic or antifungal [source: Selden].

For more information on underarm rashes, see the links on the next page.


Underarm Rash FAQ

Can deodorant cause an armpit rash?
Deodorants and antiperspirants are a common culprit of underarm rashes, called contact dermatitis. Some ingredients may irritate the sensitive skin, causing a red rash. Antiperspirants also block the pores in order to stop the release of sweat, which can ultimately cause a heat rash.
What can cause a rash in the armpit?
In addition to deodorant or moisturizing razor heads, friction can cause skin irritation in the underarms resulting in a rash. Heat rash is another cause of underarm rashes, occurring when sweat ducts are blocked and perspiration builds up beneath the skin.
What is the fastest way to get rid of an underarm rash?
First, you need to determine what is causing the rash. Many rashes disappear on their own in a few weeks, but there are things you can do to reduce symptoms. Stop using your deodorant for a couple of days to see if the rash goes away, being sure to gently clean the area regularly. Keep your underarms dry and wear light, loose-fitting clothing. Avoid going outside in hot weather or at least keeping exertion to a minimum outdoors. Dab on calamine lotion, apply a hydrocortisone cream, or take an antihistamine.
Can you get a yeast infection in your armpit?
Yes, a yeast infection, or candida, can occur in the armpit due to high moisture, low exposure to light, poor ventilation, and constant heat. Itchiness, a burning sensation, and a dark discolored rash are the most common signs and symptoms of a yeast infection in the armpit.
How do I stop armpits from being itchy?
Try placing a damp cloth on them or dabbing on calamine lotion - this will provide some relief and can be repeated as often as necessary. Avoid scratching your armpits. While this can provide momentary relief, it further irritates your skin, which may cause an infection.

Lots More Information

Related HowStuffWorks Articles

  • Mayo Clinic. "Slideshow: Common Skin Rashes." 12/20/08 (Accessed 9/29/09) http://mayoclinic.com/health/skin-rash/SN00016
  • Mayo Clinic. "Slideshow: Common Skin Rashes -- Intertrigo." 12/20/08 (Accessed 9/29/09) http://mayoclinic.com/health/skin-rash/SN00016&slide=7
  • Mayo Clinic. "Slideshow: Common Skin Rashes -- Contact Dermatitis." 12/20/08 (Accessed 9/29/09) http://mayoclinic.com/health/skin-rash/SN00016&slide=4
  • Mayo Clinic. "Slideshow: Common Skin Rashes -- Heat Rash." 12/20/08 (Accessed 9/29/09) http://mayoclinic.com/health/skin-rash/SN00016&slide=6
  • Mayo Clinic "Heat Rash: Definition." 1/18/08 (Accessed 9/29/09) http://mayoclinic.com/health/heat-rash/DS01058
  • Mayo Clinic. "Contact Dermatitis: Symptoms." 7/31/09 (Accessed 9/29/09) http://mayoclinic.com/health/contact-dermatitis/DS00985/DSECTION=symptoms
  • Mayo Clinic. "Contact Dermatitis: Causes." 7/31/09 (Accessed on 9/29/09) http://mayoclinic.com/health/contact-dermatitis/DS00985/DSECTION=causes
  • Mayo Clinic. "Contact Dermatitis: Complications." 7/31/09 (Accessed 9/29/09) http://mayoclinic.com/health/contact-dermatitis/DS00985/DSECTION=complications
  • Mayo Clinic. "Heat Rash: Prevention." 1/18/08 (Accessed 9/29/09) http://mayoclinic.com/health/heat-rash/DS01058/DSECTION=prevention
  • Prevention Magazine Health Books. "Underarms," in The Female Body: An Owner's Manual. 1996 (Accessed 9/29/09) http://www.mothernature.com/Library/Bookshelf/Books/32/96.cfm
  • Ripper, Jill. "Candidiasis (Yeast Infection)." WebMD. 10/5/05 (Accessed 9/29/09) http://www.webmd.com/a-to-z-guides/candidiasis-yeast-infection
  • Rockoff, Alan. "Rash 101: Introduction to Common Skin Rashes." MedicineNet.com. 1/11/08 (Accessed 9/29/09) http://www.medicinenet.com/rash/article.htm
  • Selden, Samuel. "Intertrigo: Introduction." eMedicine.medscape.com. 8/12/09 (Accessed on 9/29/09)http://emedicine.medscape.com/article/1087691-overview
  • Selden, Samuel. "Intertrigo: Treatment." eMedicine.medscape.com. 8/12/09 (Accessed on 9/29/09)http://emedicine.medscape.com/article/1087691-treatment
  • WebMD "Heat Rash: Topic Overview." 8/1/08 (Accessed 9/29/09)http://www.webmd.com/skin-problems-and-treatments/tc/heat-rash-topic-overview
  • WebMD "Rash -- Age 12 and Older: Home Treatment." 8/1/08 (Accessed on 9/29/09) http://www.webmd.com/skin-problems-and-treatments/tc/rash-age-12-and-older-home-treatment
  • WebMD "Rash -- Age 12 and Older: Topic Overview." 8/1/08 (Accessed on 9/29/09) http://www.webmd.com/skin-problems-and-treatments/tc/rash-age-12-and-older-topic-overview