Food allergies in dogs can be frustrating for both pets and owners. These allergies occur when a dog’s immune system overreacts to certain food ingredients, causing symptoms like itching, digestive issues, and ear infections. Recognizing the signs of a food allergy in your dog early and understanding how to manage them can greatly improve their quality of life. In this article, we’ll guide you through the signs of food allergies in dogs and provide practical steps on what to do if you suspect your furry friend has one.

What are food allergies in dogs?

Food allergies in dogs are immune system reactions to specific proteins found in their food. Unlike food intolerances, which are non-immune related and usually result in digestive issues, food allergies involve an abnormal response from the dog’s immune system. When a dog eats an allergenic food, their body mistakes the proteins as harmful invaders and launches an immune attack, leading to various symptoms.

Common allergens in dog food include beef, chicken, lamb, wheat, and dairy. These allergies can develop over time, even to foods your dog has been eating for years without any problems.

Generally speaking, dogs are most likely to develop food allergies before 1 year of age, or older than 6 years of age.

Signs your dog may have a food allergy

Recognizing the signs of food allergies in your dog can help you address the issue promptly. Here are some common symptoms to watch for:

Skin issues: Itching, redness, hives, and hot spots are common signs. Your dog might scratch, lick, or chew on their skin more frequently.

Digestive problems: Vomiting, diarrhea, gas, and bloating can indicate a food allergy. These symptoms might appear shortly after eating or be ongoing.

Chronic ear infections: Recurring ear infections, especially if they are resistant to treatment, can be a sign of food allergies.

Paw licking or chewing: Excessive licking or chewing of paws can indicate an allergic response. This behavior often leads to redness and swelling of the paws, especially between the toes.

Respiratory symptoms: While less common, some dogs might sneeze or cough due to food allergies.

If you notice any of these signs, it’s important to consult with your veterinarian to determine if a food allergy could be the cause.

Causes and common food allergens for dogs

Food allergies in dogs are caused by specific proteins in their food that trigger an immune response. These proteins, known as allergens, can come from a variety of sources. Here are some key points about the causes and common allergens:

Any food protein can be allergenic, but certain items are more likely to cause reactions. The most common allergens in dog food are heat-stable, water-soluble glycoproteins. These include proteins found in beef, chicken, lamb, and wheat. Smaller peptides can also be allergenic.

According to studies, the most frequently reported food allergens in dogs are beef (34%), chicken (17%), lamb (15%), and wheat (14%). Other potential allergens include soy, milk, eggs, corn, walnuts, and peanuts.

Some dogs may react to multiple foods due to cross-reactivity. For example, dogs allergic to beef might also react to cow’s milk or lamb because they share similar allergenic molecules. Similarly, cross-reactions between chicken and fish or other poultry types have been reported.

Dogs with food allergies may also be sensitive to environmental allergens, like dust mites. These can exacerbate symptoms and make it harder to pinpoint the exact cause of the allergy.

Understanding these factors can help you and your veterinarian identify the allergens affecting your dog and choose an appropriate diet to manage their symptoms.

food allergies in dogs
The most common allergens that cause food allergies in dogs

Diagnosing food allergies in dogs

If you suspect your dog has a food allergy, it’s important to get an accurate diagnosis to manage their symptoms effectively. Here’s how you and your veterinarian can determine if food allergies are the cause:

Start by visiting your veterinarian. They will perform a thorough physical examination and ask about your dog’s symptoms and diet history.

The most reliable method to diagnose a food allergy in dogs is through an elimination diet trial. This involves feeding your dog a diet with ingredients they have never eaten before, usually for 2 to 10 weeks. During this period, you must avoid all other foods, treats, and even some flavored medications.

Keep a close eye on your dog during the diet trial. Most dogs show improvement in gastrointestinal symptoms within two weeks, and skin symptoms often improve within eight weeks. In some cases, it may take up to 13 weeks for all symptoms to resolve.

If your dog shows improvement on the elimination diet, the next step is a provocative challenge. This involves reintroducing a single protein to their diet at a time and feeding it for at least two weeks. Reactions can occur within minutes to weeks after eating the protein. Avoid introducing multiple proteins simultaneously, as it makes it difficult to identify the specific allergen causing the reaction.

For example, if you want to rule out beef as a potential allergen, use cooked ground beef with nothing else added to it, feed this to your dog for two weeks with their hypoallergenic diet. If there is no reaction, then you can try another protein source in the same manner.

Your vet may also perform cytology (examining cells from the skin) to check for secondary infections, which can complicate the diagnosis. Secondary bacterial or yeast infections are common in dogs with food allergies and need to be treated.

Providing a detailed dietary history, including all foods, treats, and supplements your dog has consumed, helps your vet choose the best ingredients for the elimination diet.

No blood, saliva, or hair test has been proven reliable for diagnosing food allergies in dogs. The elimination diet trial remains the gold standard for diagnosis.

What is the treatment for food allergies in dogs?

The main treatment for food allergies in dogs is to avoid feeding them what they are allergic to. This sounds easier said than done, right?!

I typically recommend one of two dietary options: a hydrolyzed protein diet or an elimination diet featuring a single protein and carbohydrate source. Here’s a closer look at each option:

1. Hydrolyzed protein diet:

Hydrolyzed protein diets are specially formulated to minimize the risk of allergic reactions. In these diets, proteins are broken down into smaller fragments, called peptides, which are less likely to trigger an immune response. Here’s why this option can be effective:

• The hydrolyzed proteins are small enough that the immune system may not recognize them as allergens, greatly reducing the chance of a reaction.

• Commercial hydrolyzed diets are nutritionally complete, providing all the essential nutrients your dog needs without the allergenic proteins.

• These diets are readily available and easy to feed, ensuring consistency in your dog’s diet.

2. Elimination diet (single protein/carbohydrate):

An elimination diet involves feeding your dog a novel protein and carbohydrate source that they have never consumed before. This approach helps identify the specific allergens causing the reaction. Here’s how it works:

• The diet is formulated with ingredients your dog has not been previously exposed to, such as venison and sweet potato, or duck and pea. This helps eliminate common allergens like beef, lamb, chicken, and dairy.

• This diet is fed exclusively for 2 to 10 weeks, with no other foods, treats, or flavored medications allowed. Any improvement in symptoms indicates a possible food allergy.

• After the elimination period, you can reintroduce potential allergens one at a time to identify the specific trigger. This method allows for precise identification and avoidance of the allergen.

It is important to note that over-the-counter “limited ingredient” diets may not be truly novel as they often use similar protein sources to other diets. Consulting with your veterinarian and using a prescription elimination diet may be more effective, especially during the diagnosis stage.

IMPORTANT READING: Read our guide on elimination diet trials in pets and the best foods for dogs with allergies

3. Supportive therapy:

In addition to dietary changes, your veterinarian may recommend supplemental therapy to help manage food allergies in your dog. These are often temporary measures but can include:

What is the prognosis for dogs with food allergies?

Unfortunately, dogs cannot be cured of food allergies or outgrow them, but the good news is that they can be effectively managed and the overall prognosis is excellent. Once the allergen has been identified and eliminated from their diet, most dogs experience a significant improvement in their symptoms.


In closing, recognizing the signs of food allergies in dogs, such as itching and licking, digestive issues such as diarrhea, and chronic ear infections, can help pet owners identify and manage this common condition. Working closely with your veterinarian, following a proper elimination diet, and possibly using supportive therapies can greatly help your dog.

If you have any questions or are concerned that your dog may have a food allergy, please contact your veterinarian for help.