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.