Maiden
For many years, I used to get bad colds, including nasal drip, headachiness, and my throat would feel like a sword swallower.
So I decided one day to desperately chew on raw cloves of garlic, hoping to cure myself - BUT!
Instead, it made it MUCH MUCH worse - which is when the light dawned that I'm allergic to garlic & onions (in non-sauteed form).
For example:
soup made with cooked (vs. sauteed) onions
or oniony herring
or garlicky pickles
On About.Com there are onion-allergy testimonials, though many of them speak of nausea, migraine, or stomach problems. However, some speak of sinus & throat problems similar to mine.