My dog had food sensitivities and changing to raw was a miracle for her. The great thing about raw is that there is no need for any filler (all kibble is high in carbs, it's what binds the kibble) Dog Food & Yeast Infections
In area's that get a real winter, the outdoor environmental allergies should not be an issue right now, but you might trade your mop and floor cleaner, for a steam mop or something similar to help kill harmful pathogens without the use of chemicals which could irritate a sensitive dog.
I would also eliminate treats and such to see if it helps, then slowly bring them back in. Perhaps give her something like an antler to chew on which is completely natural?