81 — Pet Food Allergies in Dogs and Cats: Myths, Symptoms and Elimination Diets

Pet Food Allergies in Dogs and Cats: Myths, Symptoms and Elimination Diets

Dr. Marty Greer and Laura debunk common pet food myths about corn and wheat while sharing step-by-step veterinary strategies for diagnosing genuine food allergies and sensitivities in dogs and cats.

• Symptoms & Presentation: Unlike human food allergies, pet food allergies primarily manifest as skin issues—such as intense scratching, chewing, biting and ear infections—rather than digestive upset. Only about 20% of allergic dogs show signs of vomiting and diarrhea. In cats, symptoms are heavily concentrated as intense scratching around the head and neck.
• Debunking the Corn Myth: Despite the popularity of “no corn, wheat, or soy” marketing, the most common food allergens for dogs are actually beef, chicken, lamb, wheat and dairy. For cats, the top allergens are beef, chicken and fish.
• The Inefficacy of Retail Allergy Tests: Blood, saliva and skin test kits sold online are unreliable. Veterinary dermatologists do not recommend them.
• How to Run a Strict Food Trial: The only reliable diagnostic method is a provocative food trial lasting up to 12 weeks. This involves feeding the pet either a prescription hydrolyzed protein diet (where proteins are broken down so small that the immune system doesn’t detect them) or a carefully prepared homemade diet. During the trial, the pet must consume only this food and water—no treats, rawhides or table scraps.
• Systematically Identifying Allergens: After a successful trial, owners can systematically introduce one ingredient back into the diet per week (such as beef, chicken or wheat) and track reactions on a calendar to identify specific triggers.
• Allergies vs. Sensitivities vs. Food Poisoning: Allergies prompt immune-mediated skin issues, whereas food sensitivities present as digestive discomfort, chronic diarrhea or picky eating. True food poisoning comes from spoiled foods, dead animals or unique toxins—such as a pink mold on soft cheeses (like cream cheese) that can cause seizures in dogs.
• Predisposed Breeds: Food allergies are most frequently seen in Labradors, German Shepherds and West Highland White Terriers for dogs, and in Oriental breeds like Siamese, Persian and Burmese for cats.
• Helpful Resources:
  • Homemade Diets 
  • Balanceit