Dogs have a condition called "paroxysmal respiration". It is also sometimes
called a "reverse sneeze" because it really sort of looks like the dog
is trying to inhale a sneeze. They tend to look almost like they are having
difficulty catching their breath and there is usually a snorting type sound.
It is unusual for dogs to do this more than once or twice a day when they
are affected with the problem, though. This problem does seem to be exacerbated
by allergies and it can be difficult to determine exactly what they are
allergic to. Most of the time, it is not possible to determine if there
is an underlying cause for this problem. There are a number of theories
about why it occurs, including abnormalities in the soft palate, allergies,
"post-nasal" drip and any other condition that might irritate the palate/laryngeal
area.