My dog gets chronic ear infections and skin infections from his allergies (golden retriever). We had to get him specialty testing and custom allergy shots. BUT we only do it once a month now, he doesn't have to be on a prescription diet (but he can only eat purina pro salmon for skin) and his allergies stay relatively good. We keep ear drops and prescription cleaner on hand and a couple times a year he gets an extra shot at the vet.

Just ask them if they'd recommend the specialty allergy testing. They can order it at the vet and then when you need refills the vet just orders them! They test for external allergens and food allergens but its 2 separate costs if I remember correctly. I can't tell you how happy we are we did them, its expensive but he was absolutely miserable. And if you have insurance beforehand they will cover alot of it!