I'm not sure . . . but my allergies were so much worse the year I was diagnosed. That's what I noticed. I think the medication people take for allergies can affect blood sugars, so you might want to check the instructions for any medication you might be taking.
I'm only asking because my sugars were a little wonky yesterday (after they'd been so good, too!) and the only thing I could think of was my sneezing due to allergies. I hope that was it, because that I can control.
Is there sugar in snot?
Probably in mine. No, sneezing a lot releases something (possibly adrenaline, I think) that raises your sugars. This disease is a party all the time.