Question: how do you know if you are allergic to your own sweat?
Answer: You can get itchy red hives on your skin for lots of reasons. The ones that break out when you're sweaty from a workout, nervous, or just hot are called cholinergic urticaria (CU). They're caused by nerve fibers in your sweat glands. Your skin reacts to the heat and sweat when your body temperature goes up.