Hi and WELCOME to YT. That picture looks like pyoderma to me, which is common in dogs w/ allergies.
Since you say you've been to a vet derm, why isn't she on Atopica, Apoquel, Steroids, Temaril-P, or even and OTC antihistamine?? What was discussed about allergy testing?
She sounds miserable
. There are so very many options to try, so I'm kind of confused as to why she's not on meds that actually address her specific issues if she's actually been to a Derm. I guess I'd recommend seeing a different derm then...?
Btw, pyoderma is a bacterial infection and needs prescription antibiotics in order to address it.
All derms generally recommend a fish oil for allergy dogs, I assume she is on one?
Has she been tested for yeast on her skin...has a culture been done?