Sounds to me like you were having an allergic reaction to something that you ate....hot, itchy and increased heart rate are common.......you need to ask yourself if you are allergic to any specific food groups if that is when it happened or something that you were exposed to that set the wheels in motion.....next time that happens you need to seriously seek some medical help and i would call your doc anyway and let them know it happened.
This post sound familiar, so if I repeat myself ....
I do not associate "hot", Itchy" with heart rhythm problems. So, I can't help on those two issues. As for a little faster, what is that? Rest at 80 bpm? or 120 bpm? The number matters as what you consider "a little fast" means different things to different people.