Food Allergy and Intolerance

Cutaneous Adverse Food Reaction

Also Known As:

Food hypersensitivity, food allergy, food intolerance, cutaneous adverse reaction to food


A food allergy is an allergic reaction to a substance in a pet’s diet. The causes of food allergy are individual allergens in the pet’s food, usually protein sources more often than carbohydrates. It is suspected that certain preservatives or food additives may elicit an allergic reaction in rare cases. A pet may be allergic to one or more substances in its food.

Affected Animals:

Dogs, cats. Any age, sex, or breed of dog or cat can develop food allergies. Food allergy is more strongly suspected if the first signs of itching start before the dog is 6 months of age or after the dog is 6 years of age.


Ingredients in some pet foods may cause an allergic reaction in hypersensitive cats and dogs. Reactions are characterized by itching and/or gastrointestinal disorders, and are usually responses to a protein or carbohydrate source in the diet. Food allergies are the third most common cause of itching, and account for about 10-15% of all allergic skin diseases in dogs.

Unlike pets with seasonal inhalant allergies, pets with food allergies tend to itch year round, and may not experience much relief from anti-itch medications. Therefore, it is essential to identify and remove the type of food that is stimulating the allergic response.

Some pets will have other allergies concurrently, such as fleabite hypersensitivity and inhalant allergies, which have severe symptoms when they are not controlled.

Clinical Signs/Symptoms:

The only consistent sign of a food allergy is itching, which typically continues throughout the year and may fail to respond well to medications. Various skin lesions may also occur, but there is no characteristic pattern of lesions associated with food hypersensitivity. The ears, armpits, groin, and feet may be affected more commonly than other body parts. Food allergic dogs commonly present with recurrent ear infections in one or both ears. The clinical signs of food allergies in cats are more variable than in dogs. Cats may have miliary dermatitis (multiple small crusted bumps on the skin), or eosinophilic granulomas (raised, red, raw areas of skin) Vomiting, diarrhea, and more frequent but formed bowel movements can be noted in some cases.