5 Fast Facts About Underarm Rashes

Your underarms are ticklish for a reason: The skin is very sensitive. It's OK to shave, but be careful -- shaving can cause irritation. Razors can nick or cut the skin, causing inflammation, and deodorant or bacteria can further irritate skin.

It's fairly simple to avoid a rash or infection caused by underarm shaving. Use shaving cream to ensure a smooth shave, and make slow, short strokes so you won't damage the skin. If you shave at night, wait until morning to apply deodorant to avoid further irritation [source: Prevention Magazine Health Books PLEASE LINK TO LMI].

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].

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].

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: WebMD]. The preventive measures for friction rashes are the same as for heat rash -- keep your underarms dry and wear light, loose-fitting clothing.

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.

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. 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].

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.

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.