This site has some helpful videos to see the difference between reverse sneeze, collapsed trachea, and kennel cough; it might be helpful to watch these:
http://www.yorkietalk.com/forums/yor...d-trachea.html
One of my 1 yr. old pups gets reverse sneeze when she eats too fast or gets too excited (sometimes after eating). I don't believe it does any permanent damage, but is sort of sad to watch as they go thru the honking spasms, and people who don't know what is happening think they are choking. There are a couple methods that seem to help them stop during an episode, including holding them and lifting the chin while gently stroking/massaging the neck, or a new trick I learned is to put a dot of peanut butter in their mouth (or other food), and the licking & chewing changes the configuration of the throat so the spasm stops.