Hi Janice,
Allergies are very complicated and frustrating. I always recommend treating them with multiple modalities and by combining them, a greater chance of success can be achieved. Antihistamines can be valuable in this process but as it turns out, some animals respond to certain types and don’t respond to others. We have created an antihistamine therapy chart for dogs with instructions and dosages to follow so you can try this as a treatment, please read the instructions carefully. I also have an article that reviews the different treatments you can use and the theory behind them for treating allergies and I encourage you to check out our video on allergies.
Thanks for your question and good luck!
Dr. Clayton Greenway