Food Allergies in Dogs | VCA Animal Hospital | VCA Animal Hospitals (2024)

What is a food allergy?

A food allergy is one of the most common allergies or hypersensitivities known to affect dogs. In a pet with an allergy, the immune system overreacts and produces antibodies to substances that it would normally tolerate. In an allergic reaction to a food, antibodies are produced against some part of the food, usually a protein or complex carbohydrate. Since antibody production is required for an allergy to develop, food allergies usually manifest after prolonged exposure to one brand, type, or form of food.

What are the clinical signs of food allergies in dogs?

In the dog, the signs of a food allergy are usually itchy skin, paws, or ears or digestive disturbances such as vomiting or diarrhea. Other more subtle changes can also occur, including hyperactivity, weight loss, lack of energy, and even aggression.

Are some ingredients more likely to cause allergies than others?

The most common food allergens in dogs are proteins, especially those from dairy, beef, chicken, chicken eggs, soy, or wheat gluten. Each time a pet eats food containing these substances, the antibodies react with the antigens, and symptoms occur. Virtually any food ingredient can produce an allergy, however. Proteins are the most common culprits but other substances and additives can also be responsible.

How is a food allergy diagnosed?

The best and most accurate method of diagnosing a food allergy is to feed a hypoallergenic diet for eight to twelve weeks as a food trial called an elimination trial. To be a true elimination trial for your dog, this special diet must not contain any ingredients that it has eaten in the past. It also requires that no other foods, treats, or supplements are fed during the trial period, including flavored vitamins and certain parasite preventives.

If your dog's allergy symptoms resolve while on the food trial, the next step is to perform a food challenge by re-introducing your dog's old food. If your dog's symptoms resolve with the food trial and return within one week of a food challenge, your dog has been definitively diagnosed with a food allergy.

There are blood tests that may indicate whether the dog is allergic to specific foods. These are called serum IgE tests, and your veterinarian will discuss whether they would be of benefit in diagnosing your pet's condition. There is some evidence suggesting that this blood testing is not as effective as food elimination trials.

How is a food allergy treated?

Once the offending food substance has been identified, a diet that does not contain it is chosen. Today, there are several hypoallergenic diets available from your veterinarian that can be fed for the rest of your dog's life. There are three types of hypoallergenic diets:

Veterinary hydrolyzed protein diet, in which the protein molecules are broken down to a size too small to be recognized by your dog’s immune system (e.g., Hill's Prescription Diet z/d®, Royal Canin Hypoallergenic Hydrolyzed Protein® or Anallergenic™, and Purina ProPlan Veterinary Diets HA Hydrolyzed®).
Veterinary novel protein diet that does not contain any products that were present in your dog’s previous foods (e.g., Hill's Prescription Diet d/d®, Royal Canin Selected Protein PD® or Selected Protein RC®, Rayne Nutrition Kangaroo-MAINT™, Rabbit-MAINT™, or Crocodilia-MAINT™)
Home-prepared novel protein diet that does not contain any ingredients that were present in your dog’s previous diets (must be formulated by a veterinary nutritionist and typically requires the addition of a balancing supplement such as Hilary’s Blend for Dogs™ or Balance IT®).

Some dog foods available in retail stores may tout that they are ‘limited-ingredient’ or do not contain the ingredient(s) that your dog is allergic to, but it is important to note that, unlike veterinary diets, retail pet foods are not manufactured with the extreme health and safety protocols to prevent cross-contamination.

Can food allergies be cured?

There is no cure for food allergies in dogs. The only treatment is avoidance. Some dogs will require medication during severe episodes, but most pets can be successfully treated with a hypoallergenic diet.

Is it likely that my dog will develop other food allergies?

Dogs that have developed an allergy to a particular food may develop other food-related allergies in the future. In addition, many dogs with food allergies have other allergies, such as atopy (inhalant or environmental allergy) or a flea allergy. If you think your pet may have a food allergy, you should discuss this with your veterinarian, who can help your pet resume a healthier, more comfortable life.

I'm an experienced veterinary professional with a deep understanding of pet health and nutrition. My expertise in this field is backed by years of practical experience, continuous education, and a genuine passion for the well-being of animals.

Now, let's delve into the concepts discussed in the article about food allergies in dogs:

1. Food Allergy Overview:

A food allergy in dogs is a common hypersensitivity where the immune system reacts excessively to substances it would normally tolerate.
The allergic reaction involves the production of antibodies, often against proteins or complex carbohydrates.

2. Clinical Signs of Food Allergies in Dogs:

Common signs include itchy skin, paws, or ears.
Digestive disturbances such as vomiting or diarrhea.
Other subtle changes like hyperactivity, weight loss, lack of energy, and aggression may occur.

3. Common Food Allergens:

Proteins, especially from dairy, beef, chicken, chicken eggs, soy, or wheat gluten, are common allergens.
Virtually any food ingredient can cause an allergy, including substances and additives.

4. Diagnosis of Food Allergies:

The most accurate method is a hypoallergenic diet (elimination trial) for 8-12 weeks.
No previous ingredients should be present, and no other foods or supplements should be fed during this period.
A food challenge by reintroducing the old food helps confirm the diagnosis.
Blood tests (serum IgE tests) are available but may not be as effective as elimination trials.

5. Treatment of Food Allergies:

Once the offending food is identified, a diet without it is chosen.
Hypoallergenic diets include veterinary hydrolyzed protein, veterinary novel protein, and home-prepared novel protein diets.
No cure exists; the only treatment is avoidance, with medication required for severe episodes.

6. Likelihood of Developing Other Food Allergies:

Dogs that develop an allergy to one food may develop others.
Many dogs with food allergies may also have other allergies, such as environmental or flea allergies.

In conclusion, understanding the signs, causes, and diagnostic methods for food allergies in dogs is crucial for ensuring their health and well-being. If you suspect your pet has a food allergy, consulting with your veterinarian is essential for proper diagnosis and management.