I get those "hives" too from the silicone leg grippers. It's irritating, but I can't do much about it. It really only happens on century rides when it's hot. I also get winter hives, so I have to dress warmer on my legs in the cold that I want to. I rubbed ice on my elbow tendonitis and noticed it was giving me hives. About the shorts, I found a PI pair that doesn't have silicone in the grippers, but the compression isn't as good. I like the way the compression feels, so I will have to compromise I guess.