I have battled immune problems, asthma, severe allergies and what has been labeled as 'multiple sensitivities' all of my life. This all led to serious migraines, eczema (so severe that I was asked one time if I could possibly have Leprosy), I have Rheumatoid Arthritis, another immune disorder and on and on and on.
You can, indeed, have a severe reaction to contrast dye. The first time I had contrast dye used on me was when I was 27. I got sick, threw up and was sick (like with the flu) for 3 days. The second time I had contrast dye used was about 10 years later. I DIED! I had an anaphylactic reaction and went into cardiac arrest, received CPR, had 3 Epinephrine / Adrenaline injections and they finally re-started my heart.
I found a Dr., quite by accident, that probably saved my life. Instead of trying to knock out my immune responses with steroids and other drugs that had nearly killed me, he went to the cause and identified the things that triggered my extreme immune responses and 'desensitized' me to them gradually like other allergists do with ordinary allergies.
I will PM you with his name and contact information a little later in the day when I get back in.