Why do my dog sneeze when he gets excited?

I have a now 5 year old Shih tzu name Bayley and every time I come home or he sees that I grab his leash to go walking, he gets overly excited, starts turning on around, then sneeze. When I come home, I call his name, "Hey Bayley!" he then goes overboard and run around the house, jump on couches, jumps on me, and if I pet him/rub his head, oh my God, he looses his mind, turns in circles, sneezes, run all over the house. I could never just grab the leash and attach it to his collar then we go outside walking. Noooo, he has to first rapidly shake his head, body, and tail as if he's wet or something, turn around his circles, sneezes and run around the house before we go walking. Is this normal behavior?