Most definately an allergy but to what is the question. Food, maybe, environment, probably. Be sure to first off be using a good flea preventative. As for the Lamb and Rice, at one time that was used for food allergy, but over the years because it has become a staple of food for most dogs, they have now developed allergies to it. Maybe try a Duck and Potatoe that you can buy at PetSmart or other feed stores. Also, avoid any food with dyes, a big allergy culprit. The benedryl is a good start and no knowing how big your dog is, you can probably do 2 a day if its over 35lbs. Really hard to overdose on that. Also, I try a gentocin topical of some sort on the paws, or hydrocortisone to keep him from licking those. Allergy testing can be expensive. Remember, if you are thinking it could be food, do not feed anything except the dog food you are trying. If you want to give treats, find the food in the can and shape it and bake it for treats. Any deviation from the food you are testing will give you negative results. good luck.
If you think you know all the answers, it just means you haven't been asked all the questions.