Is your dog constantly scratching, rubbing or licking themselves? Do they have recurrent ear infections? If so, your dog may have a food allergy. In this article we explore the causes and signs of food allergies, and ultimately how to diagnose and treat food allergies in dogs.
What are Food Allergies?
It may surprise you to find out that dogs and humans have similar food allergens. In both dogs and humans, food allergies are caused by water-soluble glycoproteins with a molecular weight of >10,000 Daltons. Put simply, they are typically allergic to protein.
Food allergies differ from food intolerances in that a food allergy is an immune response elicited by a glycoprotein, whereas a food intolerance is related to the effect the food has on the body and can be elicited by anything from flavors to preservatives. More importantly, while a food intolerance can occur the first time your dog eats a food, a food allergy does require previous exposure – meaning your dog has to have eaten the item at least once before for the body to have an allergic response.
The Cause: What are the Most Common Food Allergens?
Many people believe that corn and soy cause the majority of food allergies in dogs, however this is incorrect. According to a research paper published in 2017, the most common food allergens for dogs are:
Our high protein plant-based dog food is inherently devoid of most of these allergens, and we took it one step further to make sure our formulas did not contain any wheat either.
Less common allergens are pork, egg, corn, and soy… and guess what? Our food does not contain any of these allergens either.
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What Dogs are Affected by Food Allergies?
If your dog has a food allergy, there is a good chance that you will know before they are a year old. In a recently published study it was demonstrated that about 22% of food allergic dogs will show signs before they are 6 months old, and about 38% will show signs before they are a year old. This means that about 40% of food allergic dogs will show signs before one year of age.
It is important to note that there are also certain dog breeds that are predisposed to food allergies, and make up about 40% of all food allergic dogs. These breeds include:
- Labradors (19%)
- German Shepherds (13%)
- Westies (11%)
How Common are Food Allergies?
In a recent study, it was seen that in dogs with skin disease, up to 24% of these dogs had a food allergy. Even more, in dogs presenting for itching, 9-40% of these dogs had a food allergy. It is important to mention here that dogs with food allergies can also have environmental allergies.
What are the Symptoms of Food Allergies?
- Non-seasonal itching
The only consistent clinical sign of food allergies is non-seasonal itching. This means that your dog is generally itchy year-round. Remember that itching doesn’t always just mean scratching, it also means paw licking, rubbing, etc. Just to note: this can also be seen in those dogs with environmental allergies to dust mites, for example.
The most commonly affected areas are:
- Rear end and around anus
- Between the toes
- Around the eyes
- Ear Infections
About 40% of food allergic dogs may have ear infections, and surprisingly this can sometimes be the only symptom seen in a food allergic dog.
The most common triggers for hives are insects, drugs and food allergies.
- Recurrent Skin Infections
Dogs with food allergies are also more likely to have skin lesions associated with itching and are more likely not to respond to steroids when compared to those with environmental allergies.
- Gastrointestinal Signs
Chronic diarrhea or soft stools with or without vomiting may be a symptom of a food allergy. Diarrhea is more common than vomiting in dogs with food allergies, but it is important to keep in mind that it only occurs in about 26% of food allergic dogs.
Other gastrointestinal signs that may be food related are increased number of poops per day (more than 3 poops/day), stomach noises, flatulence and burping, as well as blood and/or mucus in the stool. If your dog has non-seasonal itching and has more than 4 bowel movements per day, then they are likely food allergic.
- Respiratory Signs
Although not as common in dogs with food allergies, sneezing and coughing can also be a sign of food allergies.
How to Confirm Your Dog has a Food Allergy
The only reliable way to confirm whether your dog has food allergies is to perform a diet trial. This means feeding your pet a hydrolyzed or novel protein diet (such as Wild Earth) for 8 weeks. During this time, your dog is not allowed to eat any other treats or table scraps. Typically gastrointestinal signs improve within 2-3 weeks, and skin signs usually improve anywhere from 1-2 months.
If your dog does improve over this time, in order to confirm food allergies, it is recommended that you challenge your dog by reintroducing the suspected offending allergen. Typically symptoms will return within 2-3 days, but can take up to 2 weeks. Many individuals who see improvement on the diet trial and wish not to rechallenge their dog will simply continue to feed the hydrolyzed or novel protein diet.
It is important to mention that while many companies offer blood, hair and saliva tests to determine whether your dog has a food allergy, these tests are not very reliable. In a study evaluating a popular allergy test kit that uses hair, the authors tested hair from stuffed animals, confirmed food allergic dogs and non-food allergic dogs, and they found that the test was not able to differentiate between allergic dogs, non allergic dogs, and stuffed animals.
How to Treat Food Allergies
If a diet trial has confirmed that your dog has a food allergy, then it is important to continue to make sure that the offending allergen is eliminated from their diet.
Wild Earth dog food is free from the top five most common food allergens: beef, dairy, chicken, wheat and lamb. Our high protein formula is also free from less common allergens such as pork, egg, corn, and soy, making our food a great option for food allergic dogs.
It is important to remember that the allergen must be avoided entirely… and this means in treats and table scraps as well. The good news is that Wild Earth’s low calorie treats are also free from all of these common allergens, and are the perfect way to spoil your dog with none of the itching!
Tiffany Ruiz Dasilva, VMD, cVMA
Dr. Tiffany Ruiz Dasilva is the Professional Services Veterinarian here at Wild Earth. She received her Bachelor of Science degree in Biology from Brown University, and attended veterinary school at the University of Pennsylvania School of Veterinary Medicine. Since graduation, she has worked in general practice, on telehealth platforms, and in animal rehabilitation. She has worked tirelessly to gain expertise in the field of canine nutrition through numerous certifications and coursework, and plans to pursue her Masters in Animal Nutrition.