The veterinary reccommended dose is what I wrote to you earlier - this is not some random number pulled out of a hat but what the vets in my clinic (and around the country) with whom I work reccommend:
Dogs: 1mg per pound every 8 hours (or three times in 1 24 hour period).
So if your tablets are 8mg of acrivastine diphenhydramine each then a 24 pound basenji would be 3 tablets (8x3=24) - up to 3 times daily if needed.
While hives are not life threatening in and of themselves, they do indicate a reaction triggered by certain antibodies made by the immune system. When these antibodies are released in the system, they make basophils and mast cells (these are inflammatory cells) to release other substances leading to an allergic reaction in the dogs body which can affect the throat making breathing difficult - with or with out itch.
Had it been my dog, I would have treated with benadryl until the hives subsided to counter balance any negative affects that could have popped up when you least expected it.
I would also be aware that all future allergic responses have a very high chance of being much more agressive. If possible - liquid benadryl would be nice to have on hand for such on occasion.
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