I would look into your food first and see if a change is needed there.
You can also look through our Health and Diet Section.
Yorkie Health & Diet - YorkieTalk.com Forums - Yorkshire Terrier Community
There is a lot of helpful information on grooming products in our Grooming Talk Section
Yorkie Grooming Talk - YorkieTalk.com Forums - Yorkshire Terrier Community
I use different shampoo/conditioners...and I love them all. But SheaPet is good for skin conditions and smells wonderful.