My Dog Is Constantly Licking The Pads Of Her Paws.

My dog is constantly licking the pads of her paws. Usually the right front paw. Have tried eliminating gluten from her diet and cut protein and she only seems to be a little responsive to relief with duck. But now in this spring season the licking has become worse. Could it be from grass and other pollen and not her diet? I give her benedryl (one per day) but does not seem to bring relief.