How Food Allergies Can Affect Your Dog

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Allergies aren't fun for anyone, but especially not for your dog, who can't tell you what's wrong. Food allergies and food intolerances can be a real pain for you and your dog, and they can be tricky to get to the bottom of. Usually referred to as an ‘adverse food reaction’, or (AFR), an allergy is an abnormal response to a certain ingredient in the food. There are two main types of adverse food reactions: allergies, where the immune system is involved, and food intolerances, which occur without an immune component. Allergies tend to occur in reaction to protein components of the food, such as beef or chicken, while intolerances occur in reaction to other components, such as additives.

What causes adverse food reactions such as allergies?

The most common causes of food allergies/intolerance in dogs are protein sources such as beef and chicken; dairy products; and wheat. It may take months or years before your dog develops an allergic response to a particular food. However, once this has happened, there will almost always be a negative reaction to that food.

Food allergies/intolerance can occur at any age and may last a lifetime. Some dog breeds appear more likely to develop food allergies/intolerance, including West Highland White Terriers, Cocker Spaniels and Irish Setters.

Is my dog sensitive to a certain food?

Diagnosing specific food allergies in your dog can be difficult. The most common symptoms of a food allergy/intolerance are digestive upsets, skin irritation, or a combination of the two. Skin lesions on dogs are frequently located on the face, feet and ears.

Food allergies often mimic other skin diseases, and many dogs have other allergies such as flea-bite sensitivity and atopy at the same time. Dogs with chronic or recurring external ear infections should also be evaluated for food allergies.

If your dog has an adverse food reaction, you may notice some of the following signs:

Food allergy

  • Vomiting or diarrhoea
  • Poor coat condition
  • Flatulence
  • Frequent scratching or hair loss
  • Red, inflamed skin
  • Chronic ear problems
  • Poor growth in young dogs

IMPORTANT: Some signs of food allergies/intolerance are similar to those of other serious conditions, so consult your veterinarian if you notice any of these signs.

Treatment: The importance of nutrition

The main goal in managing allergies or intolerance to food is to find and avoid the food ingredient responsible. The most practical and accurate method is a dietary elimination trial, which involves removing a suspect ingredient from the food your dog eats to see if their symptoms improve. Be mindful to remove access to all other dog food, table food, treats, snacks and chew toys while you are isolating the problem ingredient.

If your dog suffers from food allergies, it’s even more important to feed them the right dog food. The food should be complete and balanced, containing as few protein-based ingredients and additives as possible.

If your dog has an allergic reaction to a certain protein source, your vet may recommend a food with specially broken-down proteins. These hydrolysed proteins, as they are called, are too small to be recognised by the body’s immune system, flying under the radar, so to speak! Another approach your vet may recommend is to feed a food with a protein source that is new to your dog, such as egg, duck, salmon, lamb, venison or whitefish, depending on your dog’s feeding history.

For accurate diagnosis and treatment options, always consult your veterinarian and ask them to recommend the best food for your dog’s condition. Never try and simply remove ingredients from your dog's diet because you could easily end up malnourishing them.

Questions to Ask Your Veterinarian:

  1. Are there any foods I should avoid giving my dog for their allergies?
    • Ask how human food can affect your dog’s health.
  2. Would you recommend a particular food for my dog’s allergies?
    • Ask about special nutritional concerns for your dog.
    • How much and how often you should feed the recommended food to your dog.
    • Discuss which treats you can feed your dog with the recommended dog food.
  3. How quickly should I expect to see signs of improvement in my dog’s condition?
  4. Can you provide me with written instructions or a handout on food allergies/food intolerance for my dog?
  5. What is the best way (email/phone) to reach you or your hospital if I have questions?
    • Ask if you need a follow-up appointment.
    • Ask if a reminder email or notice will be sent.

Reviewed by Dr. Hein Meyer, DVM, PhD, Dipl-ECVIM-CA and Dr. Emma Milne BVSc FRCVS