My retired racing greyhound came off the track with numerous health issues primarily stemming from untreated allergies. Since she had both food and environmental allergies, I put her on an elimination diet at the suggestion of our dermatologist, Dr. Newton.
I know how vital the "allergy vial" applications are for the following reason. As the vial nears empty, the potency seems to lessen and her symptoms being returning..... itching, licking, watery eyes, etc. When the new allergy vial arrives and administered, those symptoms all cool down and she's comfortable again. It seems the only side effect administering the vial is a happy and comfortable girl in retirement. It's quite extraordinary.