Hi and welcome to YT

!
Why are you thinking changing foods will help the itching? Food allergies are extremely rare. If allergies are suspected, they're most likely environmental (pollen, dust...) and if they're this bad, I'd see a Vet Derm for them.
How old is your kiddo?
For more on allergies, read this:
http://www.yorkietalk.com/forums/die...tart-here.html