Any update? Poor girl, this sounds just awful. My Marcel is having seasonal allergies (track your pollen levels at pollen.com - helpful) and Benadryl doesn't really do much for him. I'm giving it 3xday for this next week or so, and if still no relief - I'm taking him here:
Dermatology Clinic for Animals
I noticed they also have a clinic in CA, so maybe if your vet can't help - a dermatologist would be the next step.