My husband is also allergic to onions. We had to get an EpiPen because there are too many times that onions can sneak into food when eating out. The biggest example is Subway sandwiches - for some reason they often have tiny bits of onion that end up in their shredded lettuce... and since Subway is one of my husbands favorite places to eat lunch (and since he loves lettuce on his subs) he has to be really careful.