well first off the vet did it backwards
food elimination is first but 10% of the time it is food. I have gone through the same thing since my girl was 6 mos - allergies start from the time they are 6 mos to 3 years. If it is back half of dog then usually flea allergy so do you ever see fleas? My girl could not tolerate atopica either but were you giving it with a little food? I am going to pull a link i wrote a bunch of info for you to read
first off chicken is the worst protein you can feed for an allergy dog so i would first start with transitioning off a chicken food to natural balance venison and sweet potato - have you ever fed her venison? Was she spayed before or after this all started? What changed right before this all started if you think back?
Also whenever a dog has skin issues you always want a full thyroid panel done to rule out hypothyroid as it runs in this breed.
I notice you have her cut down short and i keep a longer coat as the coat protects the skin from pollen getting on it and i keep mine in a tshirt too to keep pollens from skin as double protection.
My friend lives in new jersey and she is having a time of it with her dog as well
Allergies are the worst as 90% of the time it is environmental and if so your only options are hyposensitization shots, atopica or steroids - you can minimize the itching with minimal ingredient diets and some supplements like coconut oil and probiotics help but it is tough if environmental. If it is winter there and she is still itching it can be either food related or mold allergy as there are no pollens there now or fleas.
What shampoo are you using as sometimes the chemicals in vet shampoos can aggravate them so i tend to go with a mild hypoallergenic shampoo instead.
I totally get your frustration as i have an allergy dog too and it is heart breaking
also you may want to get a dermatologist in your area as we see one and it helps as they are very good with skin and allergy issues and it saves in the long run and they tend to be more conservative in treatment with steroids and meds than a normal vet on this topic