Food Allergies and Your Dog
Allergies are unfortunately fairly common in dogs. Food allergies, in particular are the third most common allergic response in dogs — just after flea bite allergy and atopy (caused by inhaled allergens like molds, pollen, etc.). Like humans, a dog of any age can develop an allergy at any time.
Exposure to the same food ingredient over a period of time (a couple of years or more) is necessary for allergies to develop. A dog will typically be between two and six years of age when allergies are first noticed. Food allergies are not seasonal and are seen in both males and females equally. In some cases, dogs with food allergies also have inhalant allergies that make the problem even harder to deal with.
What are the Symptoms of a Food Allergy in Dogs?
Affected animals will be very itchy and may have red, irritated skin, mainly on the ears, groin, and belly. Dogs with a food allergy will typically scratch excessively, possibly to the point of losing hair in certain areas. They may lick or chew on their paws, causing redness and irritation between the toes. Ear infections will also be an ongoing problem and skin rashes may come and go. Gastrointestinal upset is another aspect of these kinds of allergies. Diarrhea and/or vomiting may be seen often, and the dog will tend to have more (both frequency and volume) bowel movements.
Common Causes of Food Allergies in Dogs
So, what actually causes food allergies? An allergy is a response by the animal’s immune system to an offending substance (usually protein) that has been recognized as “foreign.” After being bombarded by this foreign invader for a while, the body begins defending itself by producing substances to fight off the unwanted substance. These defense mechanisms cause the body to react.
The most common ingredients found in dog foods are also the most common causes of allergies. Beef, milk and dairy products, chicken, eggs, soy, corn and wheat are the most common triggers for food allergies in dogs. As more foods contain ingredients like lamb and fish proteins these days, these ingredients are also starting to become problematic for some animals.
Pinpointing Food Allergies
Allergies are frustrating for the animal, the animal’s owner, and the veterinarian. They are difficult to control without some serious effort. Diagnosis of a food allergy requires first ruling out all other causes of skin problems. Once a food allergy is suspected, your veterinarian will most likely suggest an elimination trial diet.
Here we focus on feeding the dog something completely different than what has ever been fed in the past. Eliminating potential causes of allergic responses by providing a “novel” protein and/or carbohydrate source is the goal of this new diet. During this trial, the new food (and only the new food) should be fed for a period of 8 to 12 weeks to allow time for it to work. All treats, flavored medications and other foods should be eliminated from the dog’s diet during the elimination trial period. After the elimination trial, a challenge will be given in the form of adding back one ingredient at a time to see if a reaction occurs. Once the offending ingredient has been pinpointed, a new diet can be chosen for the long term.
Elimination diets can be commercially prepared foods or can be home-cooked recipes. There are also special foods with protein sources that have been broken down into small enough particles as to not cause a reaction. These “hydrolyzed” protein foods may look strange, but they are very efficient sources of nutrition. Just switching to a different brand of food won’t do the trick, as many foods contain similar types of ingredients that most dogs have eaten in the past.
Treatment Through Dietary Changes
Food allergies are treated by avoiding the ingredient that is causing the problem. Once the elimination diet has pinpointed the culprit, your dog should stay on the food that works best to control his symptoms. Homemade diets should not be fed long-term unless under the supervision of a veterinary nutritionist, as vitamin and mineral deficiencies are difficult to avoid.
Even after your dog has gone through an elimination diet and has been doing well on a new food for some time, it is possible for new allergies to develop. Knowing the signs and methods for controlling this condition will help you to provide the best possible care for your dog, long into the future.