Myths about Food Allergies

Having experienced an extreme gastric overload over the Thanksgiving holiday, gluttony and talking about food is the furthest thing from anything we would want to discuss. It is very common for clients to come in with statements that they THINK I want to hear, such as “I'm feeding grain free, raw, gluten free, or corn-free are among several that are mentioned. As a follow-up to previous blogs, I thought I would put these in 10 myths with comments.

1. FOOD ALLERGY IS COMMON AMONG DOGS.
Confirmed cases of food allergy are actually pretty rare; only about 5 % to 10% of dogs with an allergy have a confirmed reaction to food.



2. DOGS ARE ALLERGIC TO CORN AND OTHER GRAINS.
Contrary to current marketing campaigns by many pet food companies, true corn and grain allergies in dogs are rare. Most allergies are to meat protein. In dogs, beef is the most common food allergen, while in cats it is fish. Surprisingly to some pet owners, many dogs on a grain-free diet still have symptoms of food allergy.



3. MY DOG HAS A GLUTEN ALLERGY leading to skin lesions.
Although gluten is a protein, it has not been documented to cause skin disease in dogs. The report in Irish Setters having GI issues related to wheat gluten is flawed in that the dogs in the study were genetically related.





4. MY DOG IS TOO OLD TO DEVELOP A FOOD ALLERGY.
Your dog can develop an allergy at any age, and the deciding factor is usually exposure in addition to a genetic predisposition.



5. IT CAN’T BE FOOD ALLERGIES BECAUSE MY DOG DOES NOT HAVE DIARRHEA.
Most canine food allergies manifest as recurrent skin diseases (eg. itching, skin lesions) and recurrent ear infections. Food allergies leading to diarrhea are a less common form.



6. MY DOG HAS HAD THE SAME DIET FOR YEARS SO FOOD ALLERGIES, NO WAY!
A food allergy takes time to develop. Even though the diet has not changed, the immune system response to food proteins may change. Sometimes, manufacturers change the formula slightly, without notification, which can trigger a new, unexpected allergic response.



7. I SWITCHED FROM ONE PROTEIN SOURCE TO ANOTHER AND MY PET IS STILL ITCHING, SO IT CAN’T BE FOOD ALLERGIES, RIGHT?
Often a pet owner may switch food brands but not the protein source. NOTE That MANY over the counter diets may contain ingredients that are not on their dietary labels.4 Elimination food trial of at least 10 to 12 weeks duration, with a prescription veterinary hypoallergenic diet still remain the best option for diagnosis of food allergies.

8. I DID THE FOOD TRIAL AS SUGGESTED AND MY DOG IS STILL SCRATCHING SO I NEED TO PROCEED TO ALLERGY TESTING, CORRECT?
Before allergy testing, skin infections (bacterial, fungus) and parasites (eg. fleas, mange mites) must be addressed for the food trial to succeed. In addition, it is so easy to sabotage a food trial. Was a snack provided containing a different protein? Give pills with a Pill Pocket or cheese? Give flavored medications? Did the dog get into the trash? Remember that some dogs will have environmental and seasonal allergies as well concurrent with food allergies..

9. I HEARD THAT RAW FOODS ARE BEST FOR ALLERGY DOGS.
If the raw diet consists of a raw version of the protein trigger, then the diet will still cause problems for the dogs.

10. CAN I AVOID FOOD ALLERGIES BY CHANGING THE DIET FREQUENTLY?
There is no evidence that changing diets frequently will prevent a dog from developing allergy signs. In fact, it limits the future diet trial options due to prior exposure.


The below is my family gathering for Thanksgiving. My thanks to Bradley Brodbeck for posing for my pet photo.

Betsy Sigmon DVM, Diplomate ABVP canine and Feline
Creature Comforts Animal Hospital
Cary, NC

Sources for this article: 

1) Rosenthal, M. DVM, DACVD. 2013. Sleuth out allergy problems/ 10 allergy myths. Trends Magazine. May 2013 

2) Brooks W.C. DVM, DACVD. 2013. Food Allergy Myths. The pet Nutrition corner. VIN.2013

3) Moriello, K.A. DVM. DACVD. 2009. Food Allergy: How to achieve a successful food trial. NAVC Conference.

4) Tater K. DVM, MPH, DACVD. 2013. Real or not real: Top dermatology myths debunked. VIN Rounds. January 2013.