Dog Allergies Treatment

It is really agitating because I am trying to get him to stop. I don’t know if it’s behavioral or allergies. He’s a 2 year old bichon mix. He is constantly biting his feet. He has no fleas. He is drinking mineral water, with a 10mg benadryl a day [the vet recommended]. He is on natural foods with no wheat or preservatives in it. He gets bathed about once a month with oatmeal dog shampoo. He is in good health really but he keeps biting his feet. I also got him some chew toys that he does chew on and he loves. He still does it though. Any suggestions? Any suggestions on how to lighten the patches of fur as well without using bleach for human hair? Thanks!

I recently talked with the lady who I got my dog as a puppy from and she said that the mom is allergic to wheat and fleas. She’s been on a wheatless diet now for a little over three weeks, the house has been bug bombed and baths are given weekly. But for some reason she continues to chew on the top of her back feet ( leaving bald spots with raw skin) and on the bottom of her front feet which there’s some open wounds. I’ve tried bandaging her feet up, making her wear a cone ( which she can still lift her back leg up to bite them), neosporine, diaper rash creame, and some other skin care gel I got from An-Jans.
Besiders her feet she also has red bumps on her belly. Any known solution to get her to stop chewing her feet? Is there something else I could do?
By the way I have taken her to the vet and 175 dollars later all I got was some antibiotics and was told to put her on flea medication which she is now on.

I have a 5 year old shih tzu who is an allergy baby,he eats Solid Gold dog food,which is sold only at specialty shops and health food stores for allergy dogs-it’s a really good quality food-only whole meats no by products etc. He has no fleas and is on a monthly flea pill. We recently moved and when we did he started licking his feet constantly,to the point where his whole foot will be soaking wet,he does this to all 4’s. He’s checked out at the Vet as being the picture of health-What could cause the foot issue? MAybe he’s been misdiagnosed?