A common question when evaluating allergic pets is whether a pet has a food allergy or a food intolerance. A food intolerance may be defined as when a pet cannot handle even a small amount of a particular food, meat, protein or grain source. Usually ingesting small amounts will lead to serious acute reactions, including vomiting, diarrhea, lethargy, increased gas, as well as even skin eruptions/hives and itching in severe situations. Most of the time the symptoms will resolve on their own, once the offending food has been cleared out of the system. In rare cases, hospitalization, including IV fluid therapy may be needed if reactions are excessive. Upon repeated exposure, similar or more serious intense reactions may occur.
Food allergies are typically developed over a more chronic period of time, and usually include the development of immune-mediated reactions in the digestive tract that may present as either acute development of digestive or skin symptoms or more chronic immune reactions over time. Beef, dairy, wheat and corn are common offending allergens. Diagnosis of food allergies is typically made by feeding a restricted novel protein diet over several weeks, during which symptoms will often lessen or resolve. After the dietary trial is over, the original diet or proteins are then reintroduced, and then if symptoms occur, a diagnosis of food allergy is confirmed.