The most common allergies in dogs are flea allergies, inhalant allergies and food allergies. And while it is estimated that only about 10 to 20 percent of pets have food allergies, David McGuffin, a board-certified veterinarian at Riverside Drive Animal Care Center in Dublin, Ohio, says he sees higher numbers in his region. It’s heartbreaking to watch your pet suffer while you work toward a solution, but solutions are just a definitive diagnosis away.
Food Allergies Vs. Food Intolerance
If your pooch is experiencing gastrointestinal discomfort, such as loose stools, stomach cramps, gas and burping, a food intolerance is more likely than allergies. Food intolerance is a digestive problem where a dog’s GI tract cannot digest a particular ingredient and responds with often noisy and stinky signs of rejection.
A food allergy, on the other hand, is an immune system response and most often shows up on the skin in the form of rashes and itchiness. When the immune system identifies a food ingredient or contaminant in the food as harmful, it creates antibodies to fight the food enemy. It’s an overactive immune system, says Gary Thompson, a board-certified veterinarian with West Suburban Animal Hospital in Toledo, Ohio.
“Primary food allergies are most commonly seen in younger pets, age 6 to 9 months, and older pets, age 8 to 9 years,” Thompson says, “but symptoms generally develop over time. Hypersensitivity and allergic reactions are about exposure. The young go through a couple seasons and, with time, the allergic component develops, and continued exposure makes it worse.”
That’s why even if you’ve been feeding your pet the same diet for months or years, a reaction appears to show up suddenly; really, it has actually developed slowly over time.
Common Food Allergens
The most common meat protein food allergens for dogs, according to veterinarians, are beef, lamb and chicken, including eggs. For grain proteins, the common allergens for dogs are wheat, corn and soy.
“These are most common because they are most used in commercial dog foods,” McGuffin says. “But if the pet grew up eating venison or rabbit, there’s no reason it couldn’t react to those.”
Fish and milk also can be allergens, but it’s not always the main ingredient in a food that a pet is allergic to. It might be artificial flavors and colors, like a dye. It could even be a treat, human food we’re feeding them, rawhides and more.
“Dogs eating a variety of diets tend to be more prone to allergies because they are introduced to more potential allergens,” Thompson says.
Diagnosing Dog Food Allergies
Because genetics play a part in allergies, certain dog breeds seem more prone to food allergies. These breeds include Golden Retrievers, Labrador Retrievers, Cocker Spaniels, Pugs, Scottish Terriers, Bichon Frise and many terriers.
The most common symptoms of true food allergies typically include year-round itchiness in the face, ears, feet and/or anal area, ear infections and skin infections. It can be very frustrating to see our precious dogs experience this constant itching and licking, and it’s important to take them in to the vet to prevent serious infections from developing.
A healthy dose of patience and vigilance will be helpful because food allergy diagnosis and treatment can be tricky and take time.
“All my pets have been food allergic, with my two dogs severely food allergic,” says Ann Hill, a board-certified veterinarian at Canfield Vet, Dog and Cat Hospital in Pittsford, New York. “It drove me crazy with them breaking out in bumps and hives, and experimenting with diets at home to help my pets. I know it’s frustrating. The sooner you get it taken care of, the better; the longer it goes on, the longer it takes to resolve, so don’t ignore rashes and itchiness, even if it’s just one paw they’re licking.”
When my son was little, he went through allergy testing that included blood and skin tests. It would be nice if diagnosis was this “quick and easy” for our pets. Unfortunately, both McGuffin and Hill say that while there are blood testing companies that say their tests identify food allergies, some research suggests these tests might not work reliably for all pets at this point. Consult with your own veterinarian about this option.
So the first part of the diagnosis is from the symptoms listed above, Hill says. If these only happen during certain times of the year, the dog probably is allergic to something in the environment that only shows up during that season; think hay fever for humans. When it’s consistent throughout the year, though, it’s probably a food allergy.
“Food allergies are extremely challenging to diagnose and treat, and without an accurate diagnosis you truly can’t avoid the offending food allergens,” Thompson says.
At this point, with veterinary help, we can have our pets treated for any secondary infections, such as yeast on the skin, from all the licking and scratching, ask about remedies to ease our pets’ discomfort in the short-term, and gear up for the detective work with the elimination diet and food challenge.
The Elimination Diet
The elimination diet or food trial helps isolate which foods are causing a reaction so you can avoid these in the future. Start by taking your dog off all of the foods he has been eating, including treats, rawhides, pig ears, flavored medicines (your veterinarian will help you with medication alternatives), human foods, gelatin capsules and flavored toys. Then feed your dog either a novel protein and carbohydrate he has not eaten before, such as venison and sweet potato or rabbit and rice, or a hydrolyzed protein diet in which the proteins are broken down so small that the immune system cannot recognize and attack them.
Most veterinarians recommend feeding solely this diet and water for a minimum of four to six weeks. By then, many owners already observe a change in the dog’s itching. A true trial, however, needs eight to 12 weeks to give time for infections to clear up and to get through the life cycle of the allergic response, Thompson says.
“Cooking for your pet is fine, and sometimes we need to do that during the food trial; it eliminates contamination and variation between bags [or cans], but it’s not recommended unless you do it correctly,” McGuffin says. “Pets run into trouble with unbalanced home-cooked diets, so consult with a board-certified veterinary nutritionist who can tell you what else to include and provide supplements to create a balanced diet for the dog. For the long term, make sure it becomes a balanced diet.”
The Food Challenge
Once your pet is feeling better on the elimination diet, it’s time for the food challenge. Now you re-introduce the original diet as part of daily feedings to see if the itching returns. If it does, this confirms the food allergy diagnosis, Thompson says. The reaction should be apparent within two weeks.
If there’s no reaction to the original diet, gradually add more items, such as the treats, rawhides, etc., giving a couple weeks in between each added item, until you notice that your dog has an allergic reaction. This clearly identifies which allergens the dog is reacting to and enables you to create a diet — as well as treats and other offerings — that avoids any triggers.
Donning a detective’s cap in the short term can make your dog’s long-term care and comfort much easier, because you will know what their triggers are and can prevent future exposure.
Food allergies are not curable, but you can prevent the reaction by eliminating exposure to known irritants. And if your hypersensitive or allergic pet develops reactions later on in life, you already know it’s because his immune system is more sensitive to environmental and dietary changes and exposure, and you know where to start with the veterinarian to narrow down any new triggers.