Medically reviewed by Casey Gallagher, MD Armpit rashes can be caused by allergic reactions, infections, and chronic conditions. Armpits are a common place to get rashes because the skin there is thin ...

Cause: Warm, moist armpits are the perfect environment for ... soap and apply over-the-counter creams for bacterial or fungal infections. If the bump is large, painful, or filled with pus, see ...