Food Allergies in Cats and Dogs


food allergiesNo fleas, cuts, scrapes or signs of infection—so what in the world is making your pet scratch so much? The answer could be food allergies. Of course, itching isn’t the only symptom that can be caused by your pet’s adverse reaction to the ingredients in his food. Throwing up, frequent need to use the bathroom and depression are also clinical signs of food allergies.

Your pet could be allergic to pretty much any ingredient in his food, including the primary source of carbohydrate or protein. It may surprise you to learn that most cats and dogs are allergic to the protein source in their food rather than grain or other carbs, according to Leo’s Pet Care.  It can take months or even several years before an animal starts showing symptoms at all.

Diagnosing and Managing Food Allergies

Pinpointing the exact ingredient responsible for your pet’s discomfort isn’t an easy process. There are hundreds of pet food ingredients out there and even a simple commercial variety can have dozens of components, any of which could be the allergen your pet is sensitive to.

Even though a series of blood tests is an effective procedure for identifying allergens in humans, the tests don’t work so well on animals. If your veterinarian suspects a dietary allergen is causing your pet’s health issues, he will recommend you switch him to a “restrictive” diet for several months. Lamb and rice was once a common alternative recommended by veterinarians because the two ingredients weren’t found in most commercial food brands, but that has changed in recent years.

“Now, veterinarians must turn to more exotic sources of protein such as fish, rabbit, or
venison, and carbohydrates such as potatoes or yams,” according to the University of Illinois College of Veterinary Medicine. “The veterinarian will first have owners wean pets from their normal
diet and start the elimination diet with an overlap of four days-feeding both diets at the same

If your pet has been eating the restrictive diet for three or four months without improvement, then chances are his skin and stomach problems are caused by something else. If changing food cleared his health problems up, then you can reintroduce different protein and carbohydrate sources to your pet’s diet one at a time.

Facts about Food Allergies

  • Age: Itchiness and other symptoms of food allergies are more common in adult cats and dogs that are at least a few years old. Your pet can start showing signs of allergies later in life even if he’s been eating the same food for years.
  • Symptoms: The most common symptoms of food allergies, scratching and skin irritation, are pretty generic. There are a lot of other things that cause itchy skin, including various diseases and parasites, as well as external allergens like pollen or dust.
  • Trial Diet: You can easily mess up the results of the restrictive trial diet by giving your pet table scraps, treats or anything else. You should only feed her the food recommended by your vet and nothing else for the roughly three-month duration of the trial diet.
  • Check the Label: If you know your pet is allergic to a particular protein or other food ingredient, make sure you check the back of every package of treats or food you buy for him. Even a little bit of the allergen can set off a reaction that will leave him itchy and unwell for days.
  • Severe Symptoms: While food allergies are rarely a serious health risk, it’s possible for some pets to have seizure or other extreme reactions to allergens.