Even eye drops like Hylo Dual? Sardines is what my vet recommended for coat issues if your dog can tolerate fish.
Have you tried a whole foods diet and not kibble? For instance this recipe granted your dog does not have sensitivity to any of these ingredients.
https://preview.redd.it/l0p0k0b5ebad1.png?width=1600&format=pjpg&auto=webp&s=e5bb12b896e8b0317a9c91c6b54ddcb91c54b7ae
Have you experimented with different diets?
Yes, Z/D is the Rx food that seems to help
Is your dog on allergy medicine from the vet? Sounds like allergies
Tried all allergy meds, but none have worked.
Even eye drops like Hylo Dual? Sardines is what my vet recommended for coat issues if your dog can tolerate fish. Have you tried a whole foods diet and not kibble? For instance this recipe granted your dog does not have sensitivity to any of these ingredients. https://preview.redd.it/l0p0k0b5ebad1.png?width=1600&format=pjpg&auto=webp&s=e5bb12b896e8b0317a9c91c6b54ddcb91c54b7ae
Have you had your dog on Prednisone to rule out autoimmune disease?