Violent gastro reactions for 12 hours starting about 4 hours after ingestion. General malaise for 3 to 5 days. high exposure and I have trouble breating. I haven't ended up in the ER yet, but its been close. Benedryl helps a lot but not enough to take chances. And even onion powder in a dish can trigger a mild reaction. So much fun... but we all have our problems. I can live without vietnamese but damn it looks good. (and on the plus side I used to be allergic to dogs. At about age 20 i traded dogs for onions. I can deal...).
Holy Crap..... Just about EVERYTHING either has onion or onion powder in it, not just Vietnamese food. Guess you have to prepare your own meals and not eat out a lot.