Dog Food Allergic Reaction

This is the second time we have had to change the dog food for little Holly, our Boston Terrier. I think she at the same dog food for years and then we went to a holistic dog food. She loved it and ate it for at least 3 years and suddenly she began rubbing her eyes. She rubbed them so hard they got red rings around them and even bled on her cheeks and eyebrows. So we had to change dog foods again. Now she is doing that again and we have changed her food once more. It is already starting to clear up after a few days. It is really strange.