Allergies can affect both humans and animals. In general, most allergies are caused by environmental factors such as pollen and grass, insect bites, medication, or certain foods. Environmental allergies are very common in dogs. Food allergies can occur alone or at the same time as other allergies.
What are food allergies in dogs?
Allergies occur when the body’s immune system identifies a substance as an invasive threat to the body that needs to be attacked. The immune response causes inflammation in the body.
Food allergies occur suddenly in dogs after prolonged exposure to a certain component of dog food, often a protein. Most dogs who develop food allergies have eaten the same food for a long time.
Signs of food allergies in dogs
Dogs with food allergies usually experience skin problems such as itching, redness, rashes, rough spots, flaking, crusty lesions, and hair loss. Many dogs with food allergies also have chronic ear infections. Gastrointestinal problems such as vomiting and diarrhea may or may not go along with skin problems. Less commonly, GI problems can appear on their own, but this can be viewed as a food intolerance rather than an allergy.
Food allergies usually first appear in puppies under six months of age or adults over the age of five.
Diagnosing food allergies in dogs
Before diagnosing a dog with food allergies, the veterinarian will first rule out other causes of skin problems. A full physical exam will be done and your veterinarian will look for specific signs that may suggest food allergies.
First, the dog needs to be flea free to make sure the skin problems are not related to flea bites. This requires the use of effective flea control methods all year round. Your veterinarian can help you find the right product for your dog.
Next, your veterinarian may want to rule out environmental allergies by treating them with antihistamines and anti-itch drugs. If there are signs of a skin or ear infection, your veterinarian will likely treat your dog with antibiotics and / or topical ear medications.
How to treat food allergies in dogs
The first step in treating a dog’s food allergy is to find out what ingredient is causing the allergic reaction. The only way to do this is to put your dog on a special diet over a period of eight to 12 weeks. Although blood tests and skin swabs for allergies are available in some laboratories, most veterinarians agree that these tests are not accurate enough to correctly identify food allergies in dogs.
Feeding trials and elimination diets for dogs
The purpose of a food trial for food allergies in dogs is to remove as many potential allergens from the diet as possible. Generally speaking, it’s about feeding a novel protein (something new to the dog that has never been fed before) or a diet high in hydrolyzed protein.
Your veterinarian can help you choose a quality diet with certain limited ingredients. The protein in the diet should come from a single source and be either hydrolyzed or novel (a protein your dog has never eaten).
Novel protein diets for dogs
These generally consist of an unusual source of protein (such as game, kangaroo, duck, or rabbit) and a source of carbohydrates, as well as the necessary vitamins, minerals, and nutrients needed to make dog food complete and balanced. It is important that your veterinarian help you choose a diet that includes only the listed ingredients. Specialty veterinary diets are often preferred over store-bought diets because they are designed with food allergies in mind. Veterinarians trust these diets to be pure. Some commercial limited ingredient diets contain traces of other ingredients due to cross-contamination at the processing plant.
Hydrolyzed Protein Diets for Dogs
These use proteins that have been broken down in such a way that the immune system does not recognize them as the same component. For example, a dog with a chicken allergy can do well on a hydrolyzed protein diet.
Once a dog food has been selected, your veterinarian will instruct you on how to conduct an appropriate feeding test for your dog.
Food testing must be rigorous
The most important rule of any food trial is to ONLY feed the diet with limited ingredients for the time recommended by your veterinarian (usually eight to 12 weeks). Do not feed ANY other foods or treats, unless they are made from exactly the same ingredients.
Make sure everyone in your home knows this rule. In most cases, it’s best to feed all dogs in the household the same food, or to keep them separate when they eat. Make sure all other foods (such as cat food and human food) are out of reach.
You may find that your dog’s skin problems improve by the beginning of the testing phase. Report these results to your veterinarian, but do not stop or change the food test unless your veterinarian directs you to do so.
At the end of the recommended trial period, your veterinarian will assess the result. If your dog has improved, the vet may recommend feeding the old diet for a week or two to see if the signs reappear. Or the vet may simply recommend adding extra protein ingredients to your dog’s diet gradually (for a week or two at a time) to watch for a reaction. This will help you determine which foods your dog can and cannot tolerate.
Some dogs must follow a special diet for life because of food allergies. However, you may find that your dog is allergic to only one or two proteins and can eat all of the others with no reaction. Again, work closely with your veterinarian to choose the right dog food and treat your dog’s allergies. Visit the veterinarian every six to 12 months, or as recommended by your veterinarian, for routine wellness checkups.