If your dog has an intolerance or reaction to certain food ingredients, you can work with your vet to discover what that ingredient is and then change your dog’s diet. Here’s what to know about food sensitivity.
What is food allergy?
Veterinarians estimate that food allergies cause 1% of all skin problems in dogs. Other allergic skin problems, such as allergy to flea bites, are more common. No-one knows exactly what percentage of gastrointestinal problems, such as vomiting or diarrhoea, are caused by food allergies, as pet owners often change the food they feed their dog once one type of food is tolerated. Pets who have itching skin as well as gastrointestinal problems are more likely to have food allergies.
The exact way a food ingredient in the diet causes the symptoms of food allergy is also still a mystery. Animal specialists suspect that abnormal amounts or types of protein particles from food are absorbed into the bloodstream from the digestive tract. This causes antibodies and inflammatory chemicals to be released from the cells of the digestive tract and skin, a process called “Hypersensitivity.” The skin and digestive tract may then become sensitive to food which contains that particular ingredient. Sensitivity reactions such as itching of the skin, vomiting or diarrhoea, may occur within minutes to hours, or even several days later.
Which foods cause food allergy?
Any food ingredient you’ve been feeding your dog can cause hypersensitivity reactions. The protein part of the food is the most likely culprit, often in foods such as beef, eggs, wheat gluten and lamb.
Some animals develop diarrhoea when they consume milk, although this is not a true allergy; it’s described as an intolerance, as a hypersensitivity reaction is not part of the picture.
Diagnosing food allergy
Skin irritation and scratching can result from causes other than food allergy. That’s why it’s important that you carefully consider other causes, such as allergies to fleas. If your dog’s skin damage is severe and is making him irritable and miserable, your vet may prescribe anti-inflammatory drugs until the “itch-scratch” cycle ends.
The elimination diet
To get to the bottom of the problem, your vet may ask you to list all the foods in your dog’s diet, including treats, bones and table scraps. Your vet will look through this list for foods your dog hasn’t previously eaten and he or she will then prescribe a nutritionally balanced diet that probably won’t cause allergic reactions in your dog. This type of diet is called a “selected protein diet.”
Feeding your dog only the elimination diet for the prescribed time is the best diagnostic procedure to find out if your dog has a food allergy. It may take up to 6 or even 10 weeks for the itching caused by the allergy to completely disappear, so it’s important for the elimination diet to be nutritionally complete to prevent nutritional deficiencies and ill health. Your dog may be showing gastrointestinal signs such as diarrhoea, but these usually go away within a few days.
The food challenge
To find out which protein sources your dog is allergic to, your vet may recommend testing different protein sources once your dog’s clinical signs have improved. The way you do this test is to introduce suspected food items to the diet in small quantities—one new food ingredient per week. If the itching or diarrhoea your dog previously experienced comes back, you’ve likely succeeded in your sleuth work and discovered an offending food ingredient. If, however, you don’t want to try the food challenge and your dog is happy on the elimination diet, you may continue to feed him these foods – as long as they represent a complete and balanced diet.
Guidelines for care and attention
- If your dog has been prescribed drugs, make sure you administer them exactly as prescribed.
- Make sure your dog has access to a plentiful supply of clean, fresh water. Eliminate other fluids, such as milk, at least while your pet is on the elimination diet.
- When feeding your dog the elimination diet, give him absolutely no other foods.
- You may need to separate pets in the household during feeding times.
- You may need to feed your dog the elimination diet for up to10 weeks before all the allergic signs disappear. Be patient!
- Watch your dog closely for remission or a decrease in severity of signs during the elimination diet period and let your vet know about any improvements or reactions to specific foods.