Human beings can’t survive without a stable body temperature. So we have a highly effective (most of the time) thermostat to regulate it. You get hot and your body produces sweat. The sweat uses your body heat to evaporate and your temperature should hopefully go down.
Feeling hot and sweaty is uncomfortable, but if you have cholinergic urticaria you could develop hives in addition to other symptoms. Cholinergic urticaria is a type of chronic inducible urticaria. This means the hives tend to last more than 6 weeks and are usually triggered by something. In the case of cholinergic urticaria anything that raises your body temperature, such as stress or eating spicy foods is what triggers the hives. Some people can also experience acute urticaria, where hives appear than disappear within 24 hours. This type of urticaria doesn’t usually last more than 6 weeks.
Cholinergic urticaria usually first appears in people between the ages of 10 and 30 and affects males more than females.If you have other forms of chronic hives, this can also increase your risk of developing heat allergy rash.