A food allergy in dogs can start at any age, but they are most commonly found in dogs that are 2 years of age and older. Studies have shown that dogs who consistently eat the same food each day and the same source, such as the brand of food or the same source of protein, are more susceptible of developing a food allergy. When a dogs immune system continually deals with the same type of allergens for several years, it may end up developing negative reactions toward the source of food.

Intolerance or Allergies 

It is important to not confuse food intolerance with food allergies. Both are often the most difficult aliments for pets to diagnose and the symptoms of allergies and intolerance can be uncomfortable for your dog. Food intolerance does not cause the same type of reactions as an allergy, such as skin problems and itching. In some dogs a food allergy can literally begin within a day and the allergen could be due to something the dog has eaten for years with no problems. In most cases, dogs with food allergies will the symptoms will increase and decrease overtime and new symptoms may occur as other symptoms diminish. Some of the most common chronic symptoms of allergies may include:

• Hair loss
• Flaky skin
• Skin hives and rashes
• Itchy paws and feet, which often leads to chewing at paws
• Dry skin
• Itchy skin
• Chronic vomiting
• Recurrent ear infections
• Chronic diarrhea
• Recurrent hot spots and skin infections
• Frequent bowel movements

Most common dog food allergens

It has been shown that specific ingredients that commonly found in dog foods have a higher tendency to cause dog food allergies than other ingredients. Some of the most common ingredients in dog food that may trigger food allergies may include:

• Beef
• Chicken
• Eggs
• Dairy products including cheese and milk
• Wheat
• Corn
• Soy
• Yeast
• Certain spices and/or additives

Treating Dog Food Allergies 

Dogs with a food allergy usually will not respond to a steroid or anti-histamine treatment, or they may have a limited response that only lasts a day or two, before symptoms will return. Typically treatment for food allergies in dogs is treatment with an exclusion diet. This type of diet involves removing one ingredient at a time from his diet for two weeks. In most situations this means serving him special foods or homemade food until the allergen can be identified. Once a particular ingredient is excluded and his symptoms disappear or improve, it is usually an indication that the food excluded was causing the reactions.