Have you taken your dog to the vet to get an allergy test? Are you sure it is environmental or food related? If you feel it is might be food related, I would try a home cooked or raw food elimination diet. I also live in So Cal and my male has allergies (environmental and probably some food ones), so I feel your pain. We've been able to control the itchies through diet for the most part. I was at least able to take him off antihistimes after doing an elimination diet. We also did an allergy test on environmental allergens.
Good luck!
Good luck!