First of all let me welcome you to our community. We had this discussion last week, Lexie GIrl is having semilar problems. I know what you are going through as well, I went through it.Here was my response last week.
I just went through this nightmare not to long ago. Nina & Coby had the same exact symptoms. It was driving me insane. The vet told me it was common for yorkies to have allergies. I was just trying to pin point what was triggering the allergies. He told me to give them Benadryl. First mistake! Nina had a really bad reaction to it. She had the shakes, heavy panting, well never again. Ichanged there food to Solid Gold lamb and rice, it helped a little bit but not enough. I went ahead and started to cook home mademeals which they loved, but not much of a change.
Me just going crazy and researching I came across this web site for natural medicines for animals. It has done wonders. It's been less than 4 weeks and I can honestly say Coby does not scratch anymore, Nina I have caught licking her paws just on a few occasions at night, But it's been when we have come back home from a walk. When I placed my order they told me to give it at least 6 weeks, I am so happy and relieved that it took less time to kick in.
Please check into this, it's made my life,Nina & Coby's much happier.
If you have any questions, don't hesitate to e-mail me. I'll be more than happy to answer any questions anybody might have.
http://www.carefreepet.com/index.html