my little dog has had an allergic reaction to something and her belly, armpits and inside ears suddenly turned red. I took her to the vet and he gave her an injection and she is on prednisolone for a week but it's been two days and so far and I can't see much if any improvement. she isn't as itchy but is still very red. how long do steroids take to shut down an allergy response? should I be seeing some improvement by now or is it too soon?