this seems obvious so it's probably not true, but I'll post it anyway just in case: are you given heparin or any other anticoagulant during the cath? Heparin is gotten usually from pig intestines or lungs. Some other types are synthetic.
Yes, but I have had heparin before and never had reactions...these reactions have only happened after cath
Did they happen to give protamine sulfate to reverse the heparin afterwards? If so, are you diabetic?
Or how about the local anesthetic? Did they use procaine?
Or how about the contrast dye used for imaging?
And next time, you can ask them to give corticosteroids beforehand, instead of the antihistamine, to try and lessen the reaction.