Animal Food Allergies May Be More Common Than We Think

Experts at the European Academy of Allergy and Clinical Immunology (EAACI) say we might be underestimating the prevalence of lactose intolerance and other food allergies among our furry friends. They published their report in the journal Allergy.

Rates of allergies and other autoimmune conditions are climbing in countries around the world. The cause of this increase is not totally clear, although many studies suggest that our sterilized environments and processed diets may be damaging our microbial ecosystems.

But it’s not just our bodies that are itching (or cramping, or wheezing). It’s Fido’s, and Fluffy’s, and Mr. Ed’s, too, says lead author Isabella Pali-Schöll of the University of Veterinary Medicine Vienna.

"Not only humans but basically all mammals are susceptible to developing allergies, as their immune system is capable of producing immunoglobulin E," Pali-Schöll said in a statement.

Immunoglobulin E (IgE) is an antibody released when the body meets an allergen. It’s meant to help keep us safe. The problem is that when we have allergies, our immune systems mistake harmless foods like wheat, eggs, milk, peanuts, or seafood for deadly poisons. The flood of IgE can cause hives, difficulty breathing, nausea, and anaphylaxis.

Most people with allergies are diagnosed because they decide to see a doctor about their symptoms. Animals don’t have that option (and probably wouldn’t go even if they did). The report, which reviews what we know and don’t know about our pets’ food allergies, finds that their reactions can be harder to spot.

“The true prevalence of food allergy in dogs, cats, and horses is unknown,” the authors write. Estimates vary widely depending on how the animal was diagnosed; studies have found that food allergies may affect anywhere between six and 25 percent of dogs, and 0.22 and 22 percent of cats. “In horses,” they write, “there is only anecdotal evidence with few cases documented in peer-reviewed literature.”

Diagnosing a pet’s allergies is not unlike diagnosing a person’s, except that the patient can’t describe his or her own symptoms. Veterinarians often use an elimination diet to determine the root of the pet’s problems.

"During this period of diagnosis, the animal will be fed homemade food or diet food prescribed by a veterinarian. Only then, and if there have not been any dangerous allergic reactions before, can 'normal' food be gradually reintroduced,” Pali-Schöll said.

As with human allergies, the best treatment is often just to avoid problem foods altogether. Most commercial pet foods are made with grains, meat, and soy products, which means this may be harder than it sounds, but a healthier, happier pet is worth it.

Scientists are working to develop medicines that will knock pets’ allergies out altogether. "The first few trial phases have already achieved some success,” Pali-Schöll said. “But it will take several more years for any products to see market launch and standard application.”

The bottom line, the authors concluded, is that we’ve still got a lot more to learn about how—and how commonly—these conditions affect our animal companions.