Animals – Understanding reactions to food

Food allergies in pets can be very frustrating. What looks like a food allergy could just as easily be a food intolerance, and the difference matters when it comes to managing your pet’s health.

A true food allergy is an abnormal immune response. The pet’s immune system mistakenly identifies a harmless food protein as a threat and launches an attack. This reaction typically involves the skin, causing irritation, red ears, chewing at the paws, excessive grooming or scratching. Vomiting or diarrhoea may also occur, but skin issues (particularly around the head and the backside) are often the most noticeable signs.

Food allergies can develop at any age, even in pets that have eaten the same food for years without trouble. Common culprits are animal proteins such as beef, chicken (avian), dairy, and fish. Development of a food allergy to a protein relies on a combination of genetics, and eating the protein during a time that gut tissues are inflamed.

In contrast, a food intolerance does not involve the immune system. It’s more like a digestive issue. A pet with a food intolerance might experience diarrhoea, gas or vomiting after eating a certain food, but without the itchy skin or ear problems that typically come with a true allergy.

Food intolerances may arise due to difficulty digesting certain ingredients such as lactose in dairy products, additives, meat or high-fat meals. Unlike allergies, intolerances often depend on the amount of the offending ingredient eaten.

Diagnosis is tricky

There is no simple blood or skin test that can reliably diagnose food allergies in pets. The gold standard is an elimination diet trial. This involves feeding a strict, novel-protein, vegan, or hydrolysed-protein diet – nothing else – for at least six to eight weeks. If symptoms resolve and then return when the original diet is reintroduced, it confirms a food allergy. Many times, diet trials are compromised by feeding treats or scraps that contain the offending protein. Consistency is critical for accurate diagnosis.

The only effective treatment for a food allergy is strict lifelong avoidance of the triggering ingredients.

Your vet can help you choose an appropriate commercial or home-cooked diet. Unlike seasonal allergies, food allergies don’t go away with time and can get worse with repeated exposure.

Food intolerances may be managed more flexibly, often by simply avoiding or reducing the amount of the problem ingredient.

If your pet has chronic skin or digestive problems, especially if symptoms are year-round, a food issue could be to blame. Before switching foods repeatedly, talk to your vet. A carefully planned approach is the best way to uncover what’s really going on and find lasting relief for your furry companion. Got questions about your pet’s diet? Your veterinarian is your best guide to sorting out fact from fiction when it comes to food and allergies.