Anywhere in Italy I know for sure you want a pet friendly hotel if you plan to leave them in. I've been to a few hotels here that either didn't have a "do not enter" door card or the maids would completely ignore it if I did put it up. I think Spain was the same thing they ignored the sign and still came in to clean. Nothing was missing, but I was annoyed they came into my room when I requested they did not. It all depends on where you are at, but stay in pet friendly hotels, since you would have to leave him alone when you go to dinner, or even site seeing. Most of the best places to see in Italy are the churches, and bringing a dog in there would be incredibly inappropriate. They won't even let you in if your shoulders are exposed. I would start by talking to your vet about traveling, if they do not know do an internet search for travel offices in your area and see if they have good insite for you.
Here is a link to start you out:
Taking Your Pet to Europe - Are You Sure? Pet Travel