We've got an English Bulldog also. She's been on Vet's Choice Holistic Health Extension Original since she was a puppy (1 & 1/2 years) with no problems. We've been lucky so far with no allergy problems. I still stay away from anything with by-products, wheat, corn or soy in it as a precaution. It's good you're watching the treats as well. Some people watch the dog food and then give their dogs Milk Bones or some other garbage treat.
My only other sugestion would be to add a probiotic to her rotation. I did this about 2 month ago when our dog had to go on antibiotics and I can tell the difference. Her breath doesn't smell any more and the tear stains she used to have are gone. I give her #1 PB 8 capsule a day (and I take #2). Probiotics are supposed to promote a healthy immune system. I don't know if it will help your dog, but it won't hurt.
Totally agreed on the treat thing... when we do give our dogs treats, it is usually a single piece of their kibble... of course, they are just has happy with an ice cube.
Good info on the Probiotics - thanks!
Only treats my Dogs get are mostly Apples or to a lesser degree, bits of real human food such as cheese, kosher hot dogs, etc. You'd be surprised what you can get a dog to do for a cube of Granny Smith Apple.