Symptoms of Food Allergies in Puppies

Symptoms of food allergies most often appear when the dog is between 2 and 6 years of age, but even puppies can have food allergies. Learn what causes food allergies, what the symptoms of food allergy look like and what steps need to be taken to resolve this medical condition for your dog.

How Food Allergies Develop

Food allergies are caused by an overreaction of your dog's immune system to one or more ingredients in his diet. These problematic ingredients are called allergens. The allergens cause your dog's immune system to create and distribute a chemical called histamine as an immune response to the threat your dog's body considers the allergen to be.

Histamine is the chemical that creates most common allergy symptoms. It can cause your dog to develop irritated, itchy skin, and it can cause hives to form in more severe reactions. Histamine can also upset your dog's digestive system, causing him to vomit or develop diarrhea.

Food Allergy Symptoms Appear on the Skin

Although you would think a food allergy would affect your puppy's digestive system, he will first show symptoms on his skin. The most common symptom of a canine food allergy is persistent itching and scratching. Your puppy's armpits, ears, face, front legs and hindquarters are likely to be the spots he scratches most, and he may rub his face across the floor or on furniture to try to alleviate the itching.

Other skin-based symptoms of canine food allergy can include:

  • Chewing at the base of the tail
  • Hair loss around the eyes or on the cheeks
  • Hot spots
  • Paw chewing
  • Persistent skin infections
  • Smelly skin

Your dog may also suffer from some of these problems if he has a food allergy:

  • Behavioral problems
  • Breathing problems
  • Diarrhea
  • Frequent bowel movement 
  • Recurring yeast infections in the ears

Diagnosing and Treating Your Puppy's Food Allergy

After your veterinarian eliminates other possible causes for your puppy's skin problems, he will be placed on an exclusion diet for about 12 weeks. This diet will contain sources of protein and carbohydrate that your puppy has not previously eaten. His condition will be monitored closely during the exclusion diet, and his symptoms should improve. If his symptoms have essentially disappeared during the course of the diet, your veterinarian will test the diet's effectiveness by reintroducing ingredients from your puppy's prior diet, to determine which ones are the cause of his allergies. If an ingredient causes allergic symptoms to return, it is the likely cause of your dog's problem.

To prevent future allergic attacks, you will need to alter your puppy's diet to eliminate the problem ingredient. Most dog food allergies are caused by common dog food ingredients, such as beef, chicken, corn, eggs, milk, wheat and soy. Finding an allergy-free diet may be challenging. However, many pet food manufacturers have developed specialized diets for both puppies and adult dogs with food allergies, so meeting your puppy's nutritional needs is not as difficult as it once was. In fact, most pet owners with food-allergic dogs choose to feed their pets the exclusion diet as the dog's main diet, because the pet is already familiar with the food and because it has been shown to not set off allergic reactions.