I would change the food, definitely. I'm afraid to say that Iams is actually a very low quality dog food - full of by-products and cheap grains that commonly cause allergies. Even Eukanuba is better (made by the same company) - but it's not a great food either.
Probably you won't even need to go to an allergy formula food for your dog - just something with high quality ingredients instead (and let's face it, any food can only be as good as the ingredients that go into it).
Do take a look at our feeding page at
www.boxerworld.com/feeding That page has some very good information on what to look for in a good quality food, what to avoid, and why.
Just to illustrate this, here is the ingredient list for the Iams food you're currently feeding:
Chicken,
Corn Meal, Ground Whole Grain Sorghum,
Chicken By-Product Meal, Fish Meal (source of fish oil),
Corn Grits, Natural Chicken Flavor, Chicken Fat (preserved with mixed Tocopherols, a source of vitamin E, and Citric Acid),
Dried Beet Pulp (sugar removed), Dried Egg Product, Brewers Dried Yeast, Potassium Chloride, Salt, Vitamins (Vitamin E Supplement, Ascorbic Acid, Vitamin A Acetate, Calcium Pantothenate, Biotin, Thiamine Mononitrate (source of vitamin B1), Vitamin B12 Supplement, Niacin, Riboflavin Supplement, (source of vitamin B2), Inositol, Pyridoxine Hydrochloride (source of vitamin B6), Vitamin D3 Supplement, Folic Acid), Calcium Carbonate, Choline Chloride, Minerals (Ferrous Sulfate, Zinc Oxide, Manganese Sulfate, Copper Sulfate, Manganous Oxide, Potassium Iodide, Cobalt Carbonate), DL-Methionine, Rosemary Extract
I've highlighted the ingredients most likely to be causing problems in red. First thing to note is that this is a food that is made up predominantly of corn. There is precious little actual meat in the food at all, which in itself renders it unsuitable for a canine. Well, corn is quite useless nutritionally, and along with wheat is the most common cause of allergy problems such as yours that we commonly hear of on these forums. I would not feed a food that contained corn to any dog. Beet pulp is another very common allergen.
And the other big issue with this food is that the meat main protein source is chicken by-products. Here is the official AAFCO definition of that ingredient:
a meal consisting of the ground, rendered, clean parts of the carcass of slaughtered chicken, such as necks, feet, undeveloped eggs and intestines, exclusive of feathers, except in such amounts as might occur unavoidable in good processing practice. That's just not good nutrition.
Sooo - yes, I'd switch his food immediately to something with rather better ingredients.
Since it was Iams he's been eating, as already said, I doubt that you'll actually need an allergy formula for him. Just a food with a good quantity of quality meat sources, and free of the cheap nasty grains like corn and wheat.
As suggestions, I'd try something like:
Innova or California Natural:
www.naturapet.com
Chicken Soup for the Dog Lover's Soul:
www.chickensoupforthepetloverssoul.com
Wellness:
http://www.oldmotherhubbard.com/dogs/wellness_overview.html
Fromms Four Star:
http://www.frommfamily.com/products_fourstardry.asp
Merrick:
http://www.merrickpetcare.com/
Canidae:
www.canidae.com
All of those foods are very very much better than the Iams he's currently on, and none of them contain the sorts of ingredients that commonly cause the sort of problems your guy has. You won't find those foods at Petsmart or in supermarkets, but their websites all have store locators. If none of those happen to suit you, there are plenty of alternatives in the premium food line that we could suggest here.