Did you mention you'd been working on the itching since Sierra was 9 months old? Sophie's problem is with staff infections on her underbelly. Very itchy, red, sores. We have been trying to get that under control since I got her at 4 months.
I misunderstood my vet and went through a course of various foods. Changing food proteins, grain free, etc. The misunderstandi
ng came from me trying all these foods before she reached 1 year. Their immune systems are not fully developed until then. Don't know the scientific reason, but now I can't go back to anything I tried before. Which was pretty much everything. When she recoups from surgery, we will try yet more new food. About all that is left for me is rabbit or kangaroo!?
Anyway, my point is you may want to wait until spring for new coat to come in and then try some other proteins you have not used. Especially now that Sierra is over a year old.
(Pretty long post for my 2 cents)
Good luck to you two. Glad you at least got the itching under control. If her hair doesn't come in long maybe you could enter her in the Guinness Book of World Records as the world's biggest Lab.