As a devoted dog owner, you're probably on the lookout for even the smallest sign that your pet's life is not as comfortable as you can possibly make it. So when doggie starts scratching at his belly or biting at his back, you may immediately take him or her to the vet for a flea dip. You'll also and use flea bombs all over the house in and attempt to have a flea-free environment for doggie's return.

But what if you've done all of that, and within fifteen minutes of returning home, the scratching and biting resume?

If your dog shows signs of allergies, but you are quite certain it is not from inhalants in the environment, fleas in his coat or other health problems, your dog could suffer from food allergies.

If, for example, your dog has been eating one particular food or a favorite treat for several months or even years, he or she might have developed an allergy to one of the ingredients in that food.

Your dog can go for months or even years eating the same food with no problem, but over time his or her immune system will be accumulating enough antibodies to finally result in an allergic reaction. If your dog has a bad reaction to a food the first time he or she eats it, this is a food intolerance caused by a toxin in the food (and there are, unfortunately, more of them than you’d like to think) but it’s not an allergic reaction.

While it’s natural to think that if your dog has a food allergy, he or she will exhibit indigestion like nausea or diarrhea, almost all canine food allergies cause severe skin irritation, and dogs with food allergies very often chew incessantly at their legs and paws. If your dog has intestinal distress after a meal, you are almost certainly looking at food intolerance and not an allergy.

The difficulty in diagnosing food allergies in dogs is that most dogs who are allergic will suffer from more than one allergy at a time. So even if you were to attempt to diagnose your dog’s food allergy by changing his or her diet, and your dog began experiencing the itching skin of a flea allergy, you might mistakenly think the change of diet was ineffective in treating the food allergy.

Finding the Source of the Allergy

The only way to determine that the change in diet has been effective is to eliminate all other possible causes for your dog’s symptoms, and put your pet on what is known as an "elimination trial" diet. You will feed your dog a diet which consists of a single protein and a single carbohydrate which you have never fed before, and water, for between two and three months. Because a food allergy takes months or years to develop, your dog will not be allergic to the new foods and should not become allergic to them in that amount of time.

Your vet may either recommend a commercial food which will suit the purposes of your elimination trial diet, or may suggest that you prepare your dog’s food at home. While your dog is on the elimination diet, you’ll have to be disciplined enough to avoid feeding treats or table scraps, and take away the chew toys. If there are other dogs around, keep your pet away from their droppings. Some dogs will nibble on other dogs’ waste, and even that will be enough to invalidate your elimination trial diet.

If your dog’s symptoms are seriously improved after two or three months on the elimination trial diet, you’ll know that a food allergy was causing them. If they haven’t improved, or have worsened, you’ll have to look elsewhere for their cause, but you can let your pet return to the old way of eating

One precaution: if you decide to prepare your dog’s elimination trial diet yourself, it won’t be fortified with the essential vitamins, trace minerals, and fatty acids necessary to maintain your pet’s health. So you’ll have to get supplements and add them to the food before feeding your pet.

Nothing is as unpleasant to you, a loving dog owner, as watching your cherished companion suffer needlessly. If your dog is constantly biting and itching, and you are reasonable certain that fleas are not responsible, talk to your vet about what you can do to determine if a food allergy is the culprit!