Feeding a Dog With Food Allergies: Elimination Diets

By Tailwisp Editorial TeamUpdated October 17, 20263 min read

An itchy, miserable dog is hard to watch, and food is often blamed. Food allergies do occur, but they are less common than owners think. Sorting out the cause takes patience and a careful plan.

Food allergy versus intolerance

A food allergy involves the immune system reacting to a protein, typically causing itchy skin and ear problems. A food intolerance does not involve the immune system, and causes mainly digestive signs, such as gas and loose stools. See our guide to food allergy versus intolerance.

Common signs

• Itchy skin, especially on the face, feet, ears, armpits and belly
• Chewing or licking paws
• Recurrent ear infections
• Skin infections and hot spots
• Digestive signs in some dogs, such as loose stools or frequent bowel movements
• Year-round itching, rather than seasonal

Many other conditions cause these signs, such as environmental allergies and fleas. See skin allergies in dogs and environmental allergies.

Common triggers

Studies identify beef, dairy, chicken, wheat and soy among the most common offenders, partly because dogs have eaten them most. Allergies develop after repeated exposure, so a dog can become allergic to a food it has eaten for years. Grains are less common triggers than proteins. See grain-free dog food.

Diagnosing: the elimination diet trial

Blood, saliva and hair tests are not reliable for diagnosing food allergy. The standard approach is a strict elimination diet trial.

1. Rule out other causes with your vet, such as fleas, mites and infections.
2. Choose the diet. Your vet will recommend either a novel protein diet, using a protein your dog has never eaten, or a hydrolyzed protein diet, where proteins are broken into tiny pieces. Prescription diets are often the most reliable.
3. Feed only that diet for eight to twelve weeks. No treats, flavored medications, chews, table scraps or supplements, unless approved.
4. Monitor. Record itching and ear problems.
5. Challenge. If signs improve, reintroduce the old diet to see if signs return. This confirms the allergy.
6. Identify triggers. Add single ingredients one at a time to find the culprits.

See limited ingredient diets for why over-the-counter products may not be reliable.

Tips for success

• Tell everyone in the household about the rules.
• Check toothpaste, chews and medications for hidden flavorings.
• Keep a diary.
• Prevent scavenging on walks.
• Use dog-safe treats made from the diet.
• Stay in contact with your vet.

Long-term management

Once triggers are identified, feed a complete and balanced diet that avoids them. Some dogs do well on a hydrolyzed diet long term. Others can be fed a commercial or home-prepared diet that avoids their triggers. See home-cooked dog food for the safe way to cook.

Other treatments

Dogs with food allergies may also have environmental allergies. Your vet may recommend medication, medicated shampoos, omega-3 supplements or immunotherapy. See fish oil for dogs.

When to see a vet urgently

Seek help if your dog has swollen face, hives, vomiting or difficulty breathing, since these can be signs of a severe allergic reaction. See allergic reactions in dogs.

Common mistakes in elimination trials

The most common reasons trials fail are hidden extras. A flavored chew, a lick of the peanut butter jar or a dropped crust can restart the reaction and make results meaningless. Feeding a diet for only a couple of weeks is another mistake, since skin can take much longer to settle. If a trial fails, speak to your vet before assuming food is not the cause, and review everything your dog could have eaten.

Cost and practicality

Prescription diets can be expensive, but a clear diagnosis saves money on repeated skin and ear treatment later. Ask your vet whether a sample or a trial pack is available, and plan the trial for a calm period when travel and visitors are unlikely to disrupt it.

The takeaway

Food allergy diagnosis needs a strict trial and patience. Work closely with your vet, control every morsel and enjoy the relief when your dog stops itching.

This article is general educational information, not veterinary advice. Every dog is different. If your dog is unwell, or you are unsure about a symptom, diet change or medication, contact your veterinarian.