Ingestion of one or more allergy causing substances in dog's food is referred to as dermatologic food reactions. The physical reaction is frequently excessive itchiness with resultant excessive scratching at the skin.
The entire process of a pet being sensitized to a particular agent in food and the complicated antibody response that occurs in the intestinal tract in pets with food allergies is not very well understood.
The reaction to food can be divided into 1) Food allergy and 2) Food intolerance.
Food allergies are true allergies and show the characteristic symptoms of itching and skin problems associated with canine allergies while food intolerances can result in diarrhea or vomiting and do not create a typical allergic response.
Symptoms of this condition include
Non-seasonal itchiness of any body location
Poor response to anti-inflammatory doses of glucocorticoids generally suggests food hypersensitivity
Vomiting
Diarrhea
Excessive gut sounds, passing of gas, and frequent bowel movements
Malassezia dermatitis (fungal skin infections), pyoderma (bacterial skin infections), and otitis externa (inflammation of the outer ear)
Skin plaques – broad, raised flat areas on the skin
Pustules – pus-containing raised skin inflammations
Erythema – redness of the skin
Crusts – dried serum or pus on the surface of a ruptured blister or pustule
Scale – flakes or plates of dead skin on the skin's surface
Self-induced baldness due to scratching
Abrasions/sores on the skin due to scratching
Leathery, thick, bark-like skin
Hyperpigmentation – darkening of the skin
Hives – swollen or inflamed bumps on the skin
Giant wheals (elongated marks) on the skin
Pyotraumatic dermatitis – infection of the skin wounds due to scratching excessively, and bacteria entering the wounds
