You can change his food to another protein and not have to go thru the transition phase even so that would be ok. Cant hurt thats for sure. Poor thing. Are you giving any snacks that maybe causing the hives? You can also give benedryl to help relieve the itch I believe it is 25mg per 25 pounds which should be 1 pill per 25 pounds. Make sure that it is the basic benedryl with no tylenol. As for the allergy test I would say that is up to you if you want to spend the money on it right now. You still have options at this point so you may wanna wait a bit while switching foods but if you want to do the test then by all means it may save you a headache.