I may be off base, but in case not, here are a couple of links about pups who have had PLEs. The first one, Lisstette/Manolos Mom's pup Lola took some time getting the right diagnosis and she was extremely ill and almost died while the vets tried to figure it out. Thankfully Lissette found a vet who figured it out. I believe they first thought it was lympthangectasia but it was actually histoplasmosis.
http://www.yorkietalk.com/forums/sic...g-me-nuts.html
Then, this thread which you may have seen is my Cookie who was diagnosed in Dec. 2011 with lympthangectasia and IBD.
http://www.yorkietalk.com/forums/sic...ia-update.html
It is great that your vet is seeking the opinion of a specialist! In Lissette's case the first vet didn't do that and the poor thing was SO sick.