Food Allergy

What is food allergy?

Food allergy is but one of about five specific allergies or hypersensitivities known to affect dogs. It is well known that people can be allergic to certain foods, (e.g. strawberries, nuts etc) but it is only relatively recently that food allergies have come to be routinely diagnosed in our dogs. 

What are the signs?

The main signs are pruritus (itchy skin) which is usually non-seasonal (ie occurs all year round) and sometimes, an upset bowel. Just as in children, other more subtle signs also occur.  In dogs these include hyperactivity, weight loss, lack of energy and aggression. It often occurs suddenly after months or years of consuming the diet containing the food in question.

My dog seems to scratch a lot but only periodically and at the same time have a loose bowel. Is this a food allergy?

Many dogs will occasionally react to something they have eaten. This may be due to sensitivity to a particular type of food. The symptoms are often not a true allergy but just a mild stomach upset. Once you have associated the upset with that particular food and avoid it in future, the problem is usually solved without further treatment.

Food allergy is similar but can be thought of as more profound. Antibodies are produced against some constituent of the food. In an allergic animal the immune system over-reacts and produces antibodies to other substances which normally should be tolerated in the body. 

Are some ingredients likely to cause allergies more than others?

The most common food allergies in dogs are dairy products, beef and gluten (from wheat) but any dietary protein may cause an allergic reaction. Skin irritation can also occur. Dogs with severe allergic response may show both skin and bowel problems together.

"The most common food allergies in dogs are dairy products, beef and gluten (from wheat) but any dietary protein may cause an allergic reaction."

Are these the only food constituents likely to cause food hypersensitivity?

No, virtually any food or food ingredient can produce an allergy. Proteins are the most common cause but other substances can also be responsible. As with children, food additives are sometimes found to be responsible.

How is the condition diagnosed?

Feeding an elimination diet is the ideal means of determining the presence of a food allergy. This is a diet chosen which contains none of the ingredients of the previous diet. The other alternative is to use commercially available hydrolysed protein diets. The protein in these diets has been treated with enzymes that break the base protein into small molecular fragments that are too small to react with the immune system. This is fed exclusively for a minimum of 6-8 weeks. During this time it is very important that it is the only food eaten. If the clinical signs improve on the new diet, one meal of the old diet is fed to see if the clinical signs return. Sometimes more than one diet needs to be tried before a food allergy can be ruled out.

How is the condition treated?

Once the offending constituents have been identified, a diet is organised that does not contain these particular substances. Originally one had to make one’s own diet, for example chicken and rice was a popular choice for dogs with beef protein allergies. Today there are a number of commercial diets available which are palatable, hypoallergenic and on which the dog can be fed indefinitely.

Occasionally commercial diets containing the appropriate constituents may not be available or alternatively your dog may not eat the commercial diet, in which case you may be forced to prepare a home cooked diet. We will be happy to advise you.

Can the problem be cured?

Unfortunately at present it is not possible to positively cure the dog with an allergy to food and thus as outlined above the problematic constituents just have to be avoided.

Is it likely that my dog could develop other food allergies?

It is not uncommon for dogs that have developed an allergy to one particular food to subsequently develop other food related allergies so if signs start to re-appear do not immediately jump to the conclusion that your dog has eaten some of the forbidden food. It may be that unfortunately other food related allergies are appearing. Please contact us if you have any concerns.