Hello, I m Brittany. When I get over heated, angry, or nervous I break out in hives . I ve been like this since I was about 14 years old. Seems like it only happend if I m hot or when my blood is rushing. The hives come out everywhere on my body and it itches really bad. I take benedryl for it, it dosent take the hives away but it helps the itching. This is very irritating. I itch and then when my body cools down the hives go away. Is there a diagnosis for this ? Is is something I need to be concerned about?