Does my pet have a food allergy?

The term "food allergy" is used a lot these days. Figuring out if your pet has a food allergy can be complicated. First, let's define what an allergy is. Allergies occur when the immune system (the cells in our body that normally fight infections) reacts to a foreign substance in a manner that doesn't occur in most animals. The key point to remember is that the immune system plays an important role in allergies.

The next step is to understand the different types of food allergies in dogs and cats. Food allergies can effect mostly the skin and this is called "food allergic dermatitis" or FAD. FAD will often show up as itchy skin, ear infections, skin infections, and itchiness around the perianal area in dogs. Cats often have very itchy faces and may have crusty, scaly skin. A very important point to remember is that environmental allergies to things like grass, dust mites, and pollen cause many of the same signs as FAD. Flea allergies can also look very similar. If you suspect your dog or cat has FAD, you should have your veterinarian examine them to help determine what is causing the itchiness.

Food allergies can also effect the gastrointestinal tract and often result in vomiting and diarrhea. Depending on the severity, this immune-mediated response may result in inflammatory bowel disease (IBD). It can be very difficult to tell the difference between a food allergy and a food intolerance. A food intolerance doesn't have to involve the immune system and can occur to almost any ingredient, chemical, or compound in a food. With food allergies, the immune system is usually activated by a protein it sees as foreign. Proteins are found in most food ingredients - whether it is a meat, grain, or other carbohydrate source.

Diagnosis of food allergies usually involves feeding a special diet for a period of time and watching to see if the signs improve. It is CRITICAL that your veterinarian be involved in the process of instituting a food allergy trial. The diets provided at your veterinarian’s office undergo much higher quality control standards to eliminate contamination with other protein sources. In addition, your veterinarian can provide you with guidance on appropriate treats, unflavored medications, etc.

Telling the difference between food intolerance, environmental allergens, and food allergies is challenging. Working with your veterinarian will assure your diagnosis and treatment plans are successful.

- Dr. Angela Witzel