Allergic to protein shakes?!?

I had RNY in April 05.  Since that time I have had 3 scares after drinking protein shakes.  I liken it to a mild anaphylactic reaction.  It starts with feeling my throat get tight, then I get warm all over, I develop large hives on my face, neck and chest, then my breathing gets labored.  Twice I ended up in the emergency room, the third time, I just relaxed and let it happen and my body medicated itself.  I have been to an allergy specialist and did the scratch test on my back.  She found nothing.  It is linked to three DIFFERENT protein drinks from different manufacturers.

Over the past year and a half, I have had to start getting iron infusions due to my severe anemia (related to my RNY).  Of the three different iron infusions they tried, I was allergic to two of them.  I had a very similar reaction to the protein drinks, but more intense.  I was thinking that maybe the iron in those protein drinks was the same type of iron in the infusion.  I have no idea.

I really loved drinking the protein drinks for the shear ease of getting the nutrition and protein I needed without having to eat a TON of food.  I miss them terribly.  Especially now that I am pregnant and need to eat alot more.

Has anyone had similar experiences?

 You'd have to look at the 3 drinks and see what ingredients they have in common.

Names the shakes you have tried, by Brand.

Did you try oral irons? Which ones? How many mg?

I'm trying to figure out how to get around these issues for you.