[El]

Hi Bobby D, welcome to the DFA forums 😉

“Is it possible for a dog to be allergic to a certain food and have them be symptom free for over a month”
Yes
“or should an allergy show up much sooner than that?”
Maybe

The first thing I would do is take him to a regular vet if you haven’t done so already. I would definitely take advantage of my vet’s expertise and experience before I do anything else. Once you have a better idea of what is actually going on with his skin then you could always find out what worked for other dogs with the same diagnosis. Your vet could take one look and know what it is (hopefully). Or your vet could immediately narrow it down to environmental, or food, or fleas, or yeast, or ???

If it’s food related I would do an elimination diet before I would ever put him on a veterinary prescription food like “Royal Canin Hydrolyzed Protein”. Here are the ingredients;

Royal Canin Hydrolyzed Protein
“Brewers rice, hydrolyzed soy protein, chicken fat, dried plain beet pulp, natural flavors, monocalcium phosphate…”

It’s just rice sweepings, hydrolyzed soy and vitamins and minerals to balance it, and it costs about $100 for a 25lb bag!!!

With a TRUE elimination diet you would pick 1 protein and 1 carbohydrate that he has never eaten before and feed ONLY those 2 things for at least 12 weeks.

Once you see a vet, please come back and let us know what’s going on!
Best of luck to you and your furry one 😉