Hello All ! I have 2 Yorkies, male and female. The male is 1 1/2 yrs. old, and based on what I've read about yorkies, apparently has the "typical" yorkie skin conditions/allergies.

I believe he's allergic to fleas and grass, so I bathe him (and my female) once a week and brush them alot and use natural products to keep the fleas at bay (neem oil added to shampoo/clove oil spray, etc.). I've ordered some special shampoo and spray for sensitive skin to see if that will help with the red patches that he chews on which in turn, causes sores and hair loss. My question is does anyone know of something internal that yorkies can take (preferably something natural) that may help keep allergies/redness/itching at bay? I know it's not caused by any of the products I am currently using because I've already done the elimination process on those.
As a side note - they do get Vitamin E every day (I break a capsule open and squeeze it on a piece of bread) and also, I'm going to get brewer's yeast and add to their dog food, which I've read helps keep fleas away because fleas don't like the way it tastes. Also, I have started giving him Benadryl to see if that will help with the allergy part of it, but since I just started that, I haven't had a chance to tell if that is helping yet.
Any help you all may be able to offer for this redness/scratching and chewing will be greatly appreciated !!!!