ALast night I sifted dry ingredients for five carrot cakes including 2 t of cinnamon/batch. There was much sneezing. Last night my throat and nose were burning. Today I my sinuses are a mess. So... Cinnamon or coincidence--thoughts?

Maybe it is the cinnamon, because of sifting so much. I have never had that problem with cinnamon. Hope you feel better.

Cinnamon can definitely be an irritant, just like pepper! It sounds like a reasonable explanation.
 

believe it or not this was a fad earlier this year http://www.youtube.com/channel/HCnUzWlDduDYs Just proves people are stupid. The cinnamon challenge

AI've seen that on the news and heard people have been taken to the ER after. Idiots.

My worse experience with cinnamon was with 'cinnamon oil' for a batch of homemade lollypops.  I added the cinnamon oil into the hot sugar syrup (just as I have previously with other flavorings) and it steamed up in a cloud and burned my face and neck.  It was a painful red burn to my skin, and it hurt.  I don't use liquid cinnamon extract or oil anymore.

I have never sifted cinnamon.  I stir it into the flour mix after sifting..  Cinnamon is very strong spice.