Why do coffee and chocolate make me sneeze?

I've had this (possible) allergy for as long as I can remember, but whenever I drink my morning coffee, and also whenever I eat chocolate (especially dark, bitter chocolate), I immediately start sneezing. It's not painful or anything extreme, but it happens like clockwork. It goes away as soon as I stop eating/drinking, and there are no other side effects. Anyone have this, or have heard of something similar?