Wow, talk about people blowing things out of proportion in the GD thread. You can not possibly diagnose it via a picture, especially if you're veterinarian didn't in person. The neck and shoulder region is a very common spot for dogs to scratch with their rear legs and i'm sticking with my initial comment that those marks are self inflicted. Obviously i can not diagnose it online but most allergic conditions will resolve with steroids in order to suppress the bodies immune system which is causing the reaction. It could be a local (contact) allergy, something general (food or general environmental allergy). I would not jump right on the sarcoptic mange bandwagon; that is one of those "worst case scenario" diagnoses. While i can not diagnose it and i can not tell you what it isn't, those are my initial thoughts. Its certainly tough since you are the messenger. Unless they live in a highly rural area, or are still working on a diagnosis with the original vet (pending test results, etc) then i would highly recommend seeking a second opinion.
BTW you know the internet is full of shit right???
I would never, ever ask medical advice (pet, person, etc) online because everyone thinks they know everything. Not to knock anyone on the site here but just because you own a dog does not qualify you to make any sort of treatment recommendations for anything.
Take things with a grain of salt and continue working with the veterinarian. Certainly if the vet can not solve the problem, some yahoo from a different profession who frequents ar15.com is not going to be able to diagnose your dog, lol!
PS: I'm a licensed veterinarian.