Persistent itching, recurrent ear infections, digestive upset and dull coats are common in pets and often indicate a food reaction. Distinguishing food allergies from sensitivities can be confusing because their symptoms often overlap. However, understanding the difference is essential to arrive at an accurate diagnosis, effective dietary strategies and better long-term outcomes.

Food allergies occur when the immune system misidentifies a normally harmless food as a threat and triggers an inflammatory response. According to a 2023 article published in the Journal of the American Veterinary Medical Association, when the immune system’s tolerance to food breaks down, the response involves either antibodies or immune cells like T-cells. Common symptoms include persistent itching, recurrent skin or ear infections, vomiting, diarrhea or a combination of skin and tummy symptoms. Over time, even small amounts of the offending ingredient can provoke noticeable reactions.

Food sensitivities, also referred to as food intolerances, differ from food allergies because they do not involve antibodies or immune cells. Instead, food intolerance arises when foods overwhelm the pet’s digestive capacity, its metabolism or its normal gastrointestinal function. Common symptoms include intermittent diarrhea, gas, vomiting, variable itching and changes in energy or behavior, with reactions often appearing hours or days after the food was eaten.

Although food allergies and food sensitivities can exhibit similar skin and gastrointestinal signs, veterinarians differentiate between them based on reaction patterns, dose sensitivity, timing and response to dietary intervention, rather than relying solely on symptoms.

 

Dietary Triggers and the Role of Elimination Diets

Food allergies are most often caused by specific proteins. A 2016 study published in BMC Veterinary Research indicates that the most prevalent allergens in dogs include beef, dairy, chicken, wheat and lamb; while in cats, beef, fish and chicken are most frequently implicated. Food sensitivities, on the other hand, are usually related to how the pet’s body handles certain ingredients. These reactions may occur when foods are highly processed, contain additives or are difficult for the pet to digest, rather than being caused by the immune system.

The most reliable way to identify the problematic food is through an elimination diet, followed by gradual reintroduction of ingredients. During the elimination phase, pets are fed a simplified diet with ingredients they have rarely or never eaten. All treats, flavored medications, supplements and table foods are removed during this process. This phase typically lasts eight to 12 weeks, although chronically affected pets may require a longer duration. Signs like itching, vomiting, diarrhea or ear problems are meticulously monitored. Once symptoms improve or stabilize, individual ingredients are slowly reintroduced one at a time, with several days separating each addition. If symptoms return after a specific ingredient has been reintroduced, that food is identified as the trigger.

A 1994 study published in the Australian Veterinary Journal demonstrates that an elimination diet can lead to improvements, and the recurrence of symptoms confirms food-related reactions. This method also helps veterinarians determine whether the reaction is more consistent with a genuine allergy or a non-immune sensitivity, thus guiding long-term dietary management.

Supporting Healing From the Inside Out

Dr. Peter Dobias, a conventional and integrative veterinarian, emphasizes that food sensitivities and food allergies should be viewed as expressions of deeper systemic imbalances rather than isolated dietary shortcomings. He explains that regardless of whether a pet develops a sensitivity or an allergy, the underlying contributors frequently overlap. These include genetic predisposition, toxin accumulation, nutrient deficiencies, gut dysbiosis (imbalance), chronic stress and limited dietary diversity during early development.

Dobias treats both allergies and sensitivities with foundational restoration rather than symptom suppression. His approach includes feeding species-appropriate, minimally processed whole foods; providing essential nutrients like omega-3 fatty acids, probiotics, vitamins and minerals; supporting liver detoxification; and maintaining spinal and structural health. While allergies often appear more acutely and require immediate management, he stresses that addressing underlying imbalances benefits both conditions.

“Allergies are a signal that the body’s systems and metabolism need support, not just that a single food needs to be eliminated,” Dobias asserts. This perspective helps explain why quick dietary fixes often fail. Removing a single ingredient without addressing digestive capacity, detoxification or inflammation may temporarily reduce symptoms, but it does not resolve the conditions that allowed reactivity to develop. Effective dietary intervention therefore requires structure, patience and a broader understanding of how food interacts with the whole system.

 

Ruth Roberts, an integrative veterinarian and holistic health coach for pets, is the creator of The Original CrockPet Diet. Learn more at DrRuthRoberts.com

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