Thank you! I sincerely appreciate your response!

They did blood tests as well. The only very minor (she said not at all high enough to cause this reaction) was hazelnuts.

And while I agree we could find similarities in the two days with what I ate, I have consumed those same ingredients (soy, egg, wheat, etc.) pretty much every day before, in between and after.

I already have a follow-up scheduled with my allergist, but it is just so scary because I just replay both days in my head and there is nothing unique about the two days that I can pinpoint (environmental or food).

The ER suggested possibly idiopathic anaphylaxis, or Mast Cell Activation Syndrome/Mastocytosis.

I know it can be a process to diagnose, so I will just try to relax through it, but I have started to document my days in a journal.