I also live in MD-welcome! Maybe we are neighbors!
Have you tried seeing a dermatologist for allergy testing? My yorkie, Puff, is 17 months old. She has been itchy for several weeks. Our vet put her on Prednisone and said the next step would be the testing.
I can't imagine dealing with an itchy pup and getting nowhere-I hope you both find relief soon!
__________________  Shannon & Puff 
"All his life he tried to be a good person. Many times, however, he failed; for after all he was only human. He wasn't a dog." Charles M. Schultz |