The best treatment for an allergic dog is to identify the cause and remove it from the environment. I remember testing one Golden retriever and learning he was allergic to wool. The owner got rid of the wool carpeting and wool blanket on his bed and he was cured. Unfortunately, not all allergens can be removed. For these cases, I recommend Allergen Specific Immunotherapy (ASIT). Although it is costly, this treatment has the fewest long-term side effects for the dog.
A small amount of the offending allergens are made into a vaccine that is injected into the dog. The concentration of these allergens starts out low and builds as the dog becomes less and less sensitive to them. About seventy-five percent of the dogs treated will improve.
When I place a dog on ASIT, I send the owners home with the following directions:
1) Follow the injection schedule carefully. Do not alter it without talking to your veterinarian. A sudden change might undo everything.
2) After giving the injection, observe your dog for three hours. In rare cases, dogs may suffer allergic reactions that need emergency treatment. I had one patient that got hives everytime the concentration was increased.
3) Keep the vials refrigerated. If they are left out, the allergen might decompose and/or bacteria might colonize the vial.
4) Be patient! It may take up to one year before any positive effects are seen. During this time, the pet might still require other therapies to keep them comfortable.