That doesn't sound normal for a summer coat. Have you pinpointed your dog's allergy? I ask because she still might be reacting to something.
I went down the same road with my lab. It turned out she is severely allergic to chicken and also has problems with rice. It took forever to pinpoint the allergies, but now that I have I'm militant about reading labels and Sol is doing great. Her fur grew back, her gut stabilized, and she's doing great.
You probably already know this, but part of the deal with having an allergic dog is making sure what she is allergic to is never, ever in her reach. I found food for my pup that did not have chicken in it when I first got her (not easy to find). Even the cat food does not have chicken in it. When I have chicken for dinner I fix my plate then put the rest immediately into the fridge so she can't get it off of the counter. It took a few mistakes before I really grasped how important this is.