Food Allergies in Dogs

While worrisome upon discovery, food allergies in dogs are rare but manageable. Usually, a food allergy will appear suddenly after prolonged exposure to a food allergen. Food allergy symptoms vary in severity and often overlap with other conditions, so it's important to take your dog to the vet to narrow down the possible causes. Some of the more notable symptoms include ear infections and gastrointestinal issues. The best way to diagnose a food allergy is by process of elimination by adjusting your dog's diet under your vet's supervision. Food allergies are not curable, but you can successfully manage them with a hypoallergenic diet. Your dog's allergy will not go away on its own, so treatment is necessary to relieve your dog of pain and discomfort.

What Are Food Allergies?

Food allergies occur when the body's immune system identifies a substance as an invasive threat to the body that must be attacked. The immune response causes inflammation in the body.

Food allergies tend to occur suddenly in dogs after prolonged exposure to a specific ingredient in dog food, often a protein. Most dogs that develop food allergies have been eating the same food for a long time.

Symptoms of Food Allergies in Dogs

Food allergies will typically first develop in puppies under six months or adult dogs over age five. The symptoms of food allergies in dogs can easily be misattributed to other conditions, so if you're not sure why your dog is experiencing discomfort, a trip to the vet is best.

Skin Issues

Dogs with food allergies typically experience skin issues like itching, redness, rashes, raw spots, flaking, crusty lesions, and hair loss. The allergic reaction will likely occur between six and twenty-four hours after ingestion. This is in response to the inflammation caused by the allergen.

Chronic Ear Infections

Many dogs with food allergies will have chronic ear infections. The ear infections can sometimes be attributed to a dietary excess of grain and sugar. The sugar and grain excess can lead to yeast buildup in the ears, resulting in infection.

Gastrointestinal Issues

Gastrointestinal problems like vomiting and diarrhea may occur alongside skin issues. Less commonly, GI problems may occur independently, but this may be considered a food intolerance rather than an allergy.

Behavioral Changes

Some dogs will experience behavioral changes due to repeated exposure to an allergen. These changes include hyperactivity, increase or decrease in energy, weight loss, or aggression from the stress of constant discomfort.

Causes of Food Allergies

A dog's food allergy is caused when its immune response, usually to a protein like egg, dairy, chicken, or soy, creates inflammation. Otherwise, allergies usually stem from genetic predisposition or environmental exposure early in life.

Diagnosing Food Allergies in Dogs

Before diagnosing a dog with food allergies, your vet will first rule out other causes for skin problems. Your vet will conduct a complete physical examination and look for specific signs that point to food allergies.

First, your dog must be flea-free to ensure that the skin problems are not related to flea bites. This requires the use of effective flea control methods all year long. Your vet can help you find the right product for your dog.

Next, your vet may want to rule out environmental allergies by treating them with antihistamine and anti-itch medications. If there are skin or ear infection signs, your vet will likely treat your dog with antibiotics or topical ear medications.

Treatment

The first step to treating a food allergy in dogs is discovering what ingredient is causing the allergic reaction. The best way to do this is by feeding a special diet to your dog for about eight to twelve weeks. Although blood testing and skin swabs for allergies are available at some labs, most veterinarians agree that these tests are not accurate enough to identify food allergies in dogs correctly.

A food trial for canine food allergies aims to eliminate as many potential allergens as possible from the diet. It generally involves feeding a novel protein (something new to the dog that has never been fed before) or a diet made with hydrolyzed protein.

Your vet can help you choose a high-quality diet made with specific limited ingredients. The protein in the diet should come from one source and be either hydrolyzed or novel, a protein your dog has never eaten.

Novel Protein Diets for Dogs

Novel proteins are generally composed of one uncommon protein source (like venison, kangaroo, duck, or rabbit) and one carbohydrate source plus necessary vitamins, minerals, and nutrients to make the dog food complete and balanced. Let your vet help you select a diet you can trust only to contain the listed ingredients. Special veterinary diets are often preferred over store-bought diets because they have been developed with food allergies in mind. Veterinarians trust that these diets are pure. Some commercial limited ingredient diets will contain traces of other ingredients due to cross-contamination at the processing facility.

Hydrolyzed Protein Diets for Dogs

These use proteins that have been broken down so that the immune system will not recognize them as the same ingredient. For example, a dog with a chicken allergy may do well on a diet made with hydrolyzed protein.

Once a dog food has been chosen, your veterinarian will instruct you on conducting a proper food trial for your dog.

Strict Food Trials

The most important rule of a food trial is to feed only the limited ingredient diet for the period recommended by your vet, usually eight to twelve weeks. Do not feed any other foods or treats unless they are made of the same ingredients.

Be sure everyone in your home is aware of this rule. In most cases, it's best to feed all dogs in the house the same food or separate them while eating. Make sure other foods, like cat and human food, are kept entirely out of reach.

Your dog's skin problems may begin improving early in the trial period. Report these results to your vet, but do not stop or alter the food trial unless instructed by your vet.

At the end of the recommended trial period, your vet will assess the outcome. If your dog improves, your vet may recommend feeding the old diet for a week or two to see if it causes signs to recur. Or, your vet may recommend gradually adding additional protein ingredients to your dog's diet, usually one at a time for a couple of weeks. This can help determine what foods your dog can and cannot tolerate.

Some dogs will need to remain on special diets indefinitely due to the severity of the food allergies. However, you may find that your dog is only allergic to one or two proteins and can eat all others without reactions. Again, work closely with your vet to choose the right dog food and manage your dog's allergies. Be sure to visit the vet for routine wellness exams every six to twelve months or as your vet recommends.

Prognosis for Dogs With Food Allergies

You cannot cure your dog's food allergies, but you can successfully manage them with specialized treatments and a hypoallergenic diet. Once the allergen is identified, the best treatment is total avoidance. Exposure to an allergen can easily cause a relapse, so vigilance is essential when feeding your dog new foods. Usually, if your dog has one allergy, more will develop.

How to Prevent Food Allergies

Due to unpredictable genetic factors, food allergies in dogs aren't preventable altogether. If you begin your dog on a hypoallergenic diet beginning at puppyhood, allergic reactions may be avoidable but not preventable.