You can actually get heat rash in your armpits, though it’s not as common as getting it on more exposed parts of your body. You can get heat rash under your arms for a lot of the same reasons ...

“Heat rash is most common in hot, humid conditions,” Dr Babamiri explains. “It often affects areas of the body where skin folds or clothing can cause friction, such as the neck, armpits and ...

This sounds like prickly heat ... itchy red rash you describe. In more severe cases blisters also develop. It most commonly affects the hands, feet, armpits and chest, and those who are overweight ...