A Closer Look at Food Allergies
Food allergies occur when your pet's immune system gets confused and mistakes a protein from food as an invading protein and mounts an attack. These proteins can be present in meats, grains and vegetables. It is likely that your pet was born with this allergy, and while it often first appears before your pet reaches one year of age, it can appear at any time, even if your pet has been eating the same food for a long period of time with no problems.
A food intolerance is not the same thing as a food allergy. A food intolerance is not an immune response, and is the result of poor digestion, such as a lactose intolerance. A food intolerance is also more likely to occur the first time your pet eats a new food. Your vet is the best person to confirm whether or not your pet has a food allergy or a food intolerance.
As mentioned, proteins are often the cause of food allergies. The most common sources of proteins that can cause allergies are chicken, beef, mutton, eggs and dairy products, and less commonly corn, wheat, rice, barley and oats. An allergic response can also be triggered by chemicals such as preservatives, dyes or additives. In cats, the most common food triggers are dairy products, fish and beef.
Symptoms of Food Allergies
A pet with food allergies can experience a range of symptoms such as itchy skin and hives (tiny red bumps), chronic ear or paw inflammation or infections, gastrointestinal issues such as diarrhea, nausea, vomiting and bad gas or even swelling of the face, particularly the lips, eyelids and ear flaps. A trip to the vet is definitely recommended if your pet has any of these symptoms, as there are a variety of other illnesses which can also cause these symptoms that should be ruled out first.
Preventing Food Allergies
If you suspect your pet has food allergies, unfortunately there are no reliable tests presently available that can confirm this. The best method to determine the cause of the allergy is to start your pet on a diet elimination trial. This is where you switch your pets food to a single meat source, such as venison, duck or kangaroo, and a single carbohydrate such as peas or potato. Ideally, the protein source should be something they have never had before.
You should feed your pet this single protein diet for between six to eight, and up to ten weeks and then the protein source or sources suspected of causing the allergy can be reintroduced one at a time to see if it triggers an allergic response which typically occurs within a few days or weeks of the food being reintroduced.
During the diet elimination trial, you should avoid giving your pet treats, bones, human foods and flavored medications or supplements as they may contain other protein sources and trigger an allergic response. Treats and bones derived from the same protein source that is being trialled and unflavored medications are ok to be fed to your pet during the trial.
You and your vet may find it helpful to keep a food and symptom diary for your pet during the trial and reintroduction periods to help track your pet's response to the protein sources and the extra treats and medications you give your pet that may impact the trial.
Hydrolyzed foods are a specialized food that has been processed to break down the proteins into very small molecules so that the immune system does not think they are allergens, which should eliminate the possibility of an immune response occurring. As always, your vet is the best person to advise you on the ideal type of food to feed your pet with a food allergy.