In humans, allergy tests are commonly positive for multiple allergens when
allergies are very flared/active. In this setting, the immune system is primed to react to an overly wide range of proteins. Often, the list of offending substances will narrow once the
allergies are under control.
For example, I knew a body builder patient with terrible asthma who was found to be profoundly allergic to environmental allergens as well as chicken, broccoli, carrots, and rice. These foods were the main components of his diet. Once his
allergies were controlled, he was able to resume eating his typical diet.
I do not know if it is the same in dogs, but if so, maybe your dog will have a narrower allergy set once her immune system settles down with treatment and elimination when appropriate.