Underarm Rashes

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.

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.

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.