text: am i allergic to my own sweat? i just read one of the answers to that 'rash under my breasts' question and one person suggested that it was a sweat allergy. that rash thing happened to me once when i started playing volleyball - i put powder under there and it eventually went away. also, occasionally when i start to sweat, under my arms start to itch me. i mean once i had my arms up fixing my hair (so there was nothing rubbing against it to cause it to itch). my underarms are shaved by the way. is there anything i can do about the underarm itching thing? allergy to one's own sweat is often the folk term for something called cholinergic urticaria. this is a chronic condition where a person gets hives (small, itchy papules) whenever their core body temperature rises, whether due to ambient heat (such as being in a too-warm room), from sweating, exercise, strong emotions, and even spicy foods.