Initial Understandings for Elimination Diets

Understanding the Role of Diet in Allergic Skin Disease

Food elimination diet trials are a valuable diagnostic and management tool in dogs suffering from chronic skin or gastrointestinal conditions. These trials are often recommended when a dog presents with signs suggestive of food intolerance or allergic skin disease.

What is Allergic Skin Disease?

Allergic skin disease in dogs is multifactorial and may involve:

  • External parasites (e.g. fleas, mites)

  • Food hypersensitivity or intolerance, most commonly to:

    • Beef

    • Dairy

    • Chicken

    • Wheat

    • Soy

  • Environmental allergens, including:

    • House dust mites

    • Pollens

    • Grasses

    • Moulds

Eliminating external parasites is the first step in ruling out causes of pruritus. Once this is addressed, a food elimination trial becomes a critical next step, particularly for cases with recurring or non-seasonal symptoms.

When is a Food Elimination Diet Trial Indicated?

Diet trials should be considered in dogs showing any of the following signs:

  • Chronic or recurrent itching, especially affecting paws, abdomen, armpits, or flanks

  • Hair loss associated with licking, biting, or scratching

  • Recurrent ear infections

  • Chronic gastrointestinal disturbances, including gas, diarrhoea, or unexplained weight loss

  • Facial swelling, urticaria (hives), or sudden skin eruptions

  • Dry, crusty, or flaky skin

  • Miliary dermatitis (pinpoint crusting)

These signs may overlap with both food-related and environmental causes. A strict food trial helps to isolate dietary contributors and can guide long-term management.

What Is a Food Elimination Trial?

A food elimination trial involves feeding a dog a simplified, novel, and controlled diet for a minimum of 8–12 weeks. This typically includes:

  • A single novel protein (one the dog has not eaten before)

  • A single novel carbohydrate source, or none if feeding a raw diet

No other foods, treats, supplements, or flavoured medications are allowed during the trial.

Following the trial period, previously fed foods are systematically reintroduced one at a time to monitor for return of symptoms (the "challenge" phase).

Important Nutritional Considerations

Elimination diets can be nutritionally limited due to their simplicity. It is important to:

  • Ensure the base elimination diet is nutritionally adequate, especially if fed long term

  • Monitor for nutrient deficiencies, which may contribute to skin inflammation or delayed healing

  • Reassess and balance the diet once trigger foods have been identified

Working with a veterinarian or canine nutrition professional during this process is highly recommended.

Summary

A structured elimination diet trial is a gold-standard method for identifying food-related causes of allergic skin disease or chronic GI signs. While not a cure, this approach can significantly improve quality of life when food hypersensitivities are contributing to inflammation or discomfort. Future blog entries will outline how to structure a raw or cooked elimination diet and what to expect during the challenge phase.

Jackie Gowland