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.