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, folds up on itself, and can be hairy.

you can feel more pain in the chest area or under the arm," says O'Hare. Pain often occurs in both armpits and may radiate from the breasts. Intertrigo (sweat rash) is a term used to describe ...