Allergy vs. Intolerance
True food allergies involve an immune system response and typically cause itchy skin, especially around the face, ears, paws, and rear. Food intolerances cause digestive symptoms like vomiting, diarrhea, or gas without an immune response. Both are uncomfortable, but they require different management approaches.
The Most Common Culprits
The most frequently identified food allergens in dogs are beef, dairy, chicken, wheat, soy, and lamb. Note that these are common ingredients, not exotic ones. Dogs develop allergies to proteins they have been exposed to repeatedly over time, which is why many long-term foods eventually trigger reactions.
The Elimination Diet
The gold standard for diagnosing food allergies is an elimination diet lasting 8 to 12 weeks. Your vet will prescribe a diet with a novel protein (one your dog has never eaten) or a hydrolyzed protein food where proteins are broken down too small to trigger a reaction. During this period, your dog can eat nothing else.
Long-Term Management
Once the trigger is identified, avoidance is the primary treatment. Read all ingredient labels carefully — the offending protein often appears in unexpected products. Some dogs with multiple allergies do well on prescription hydrolyzed diets long-term. Regular checkups help ensure your dog's nutritional needs are still being met.