Cutaneous Adverse Reactions to Foods in Dogs and Cats

Food allergy (food hypersensitivity) is the term used to describe the clinical disease induced by food ingestion in which there is an immunological reaction. The immunological reaction is usually associated with dietary water-soluble glycoproteins that have molecular weights ranging from 10,000 to 70,000 kD. Food intolerance is the term used for a non-immunological abnormal physiological response including metabolic, toxic, idiosyncratic or pharmacological effects of foods or food additives. Food intolerance may be caused by digestive enzyme deficiencies, proteins, toxins, food additives, vasoactive amines and contaminants such as bacteria. In a clinical setting, food allergy and food intolerance are rarely differentiated. Thus, the phrase cutaneous adverse reactions to foods (CARF) is used to reference both conditions. One should note that this differentiation of hypersensitivity versus intolerance has been discussed for many years but, in reality, there are virtually no well-documented cases of skin-related food intolerance reported in the dog or cat. Cutaneous disease appears to be seen only in truly food allergic patients.