This makes me sound like I browse WebMD and then believe that I have every malady out there but I've been diagnosed with Exercise-Induced Anaphylaxis and Urticaria (http://www.aafp.org/afp/2001/1015/p1367.html). However, my doctor indicated that even vibrations can set it off. I once broke out in hives while just standing at a concert. The boom-boom-boom of the beats over the course of a couple of hours was, apparently, enough to bring out the hives. Shit sucks. I have to take Zyrtec to exercise, take a flight, go to a concert, or use my jackhammer.