I would take her to a vet for evaluation – sounds like she has an allergy or skin condition developing and you will need help to resolve it.
In the mean time I would remove all grains from her diet, including treats. Dogs don’t need grains and don’t digest them well. And while not every dog is allergic to grains the can cause just enough impact on the immune system that other allergies can get a food-hold. Go to a good pet store (not grocery store, big box store, nor a pet store that sells puppies) and ask to be shown to the grain-free dog food area. Then start reading labels, you want a dog food that has real meat listed as the first 2 (or even better, 3) ingredients. Real meat is easy to spot, it will say lamb, elk, bison, turkey, salmon meal, whitefish meal, etc. (meal is the entire animal ground up and dried).
Don’t buy any food that lists ‘by products’ in the ingredients – you would be paying premium price for an inferior product.
Avoid chicken and beef – many dogs are reactive to these sources of protein.
If the vet recommends Benadryl use Zyrtec instead – I find that it works better for dogs.
Good luck
Often when a dog decides to stop eating it means that they are going to die. Eleven is an old dog when it is mixed with wolf. Since the dog has been seen by a doctor I would suspect there is not much to be done for this dog save to make him comfortable (manage his pain).
So sorry to hear of his troubles.