Food allergies account for about 10% of all the
allergies seen in dogs and cats. It is the third most common cause after flea bite allergies and atopy (inhalant allergies).
With the advent of lamb and rice diets many people feel that they are preventing or
treating food allergies. The fact is that nothing could be farther from the truth. The
entire process of a pet being sensitized to a particular agent in food and the complicated
antibody
response that occurs in the intestinal tract in pets with food allergies are not very well
understood. Despite our lack of understanding of the actual disease process, there are
many things that we do know including the symptoms, how to diagnose food allergies, and
also how to treat them.
Food allergies affect both dogs and cats. Unlike atopy, there
is no strong link between specific breeds and food allergies. Food allergies affect both
males and females and neutered
and intact animals equally. They can show up as early as five months and as late as 12
years of age, though the vast majority of cases occur between 2 and 6 years. Many animals
with food allergies also have concurrent inhalant or contact allergies.
Food allergy or intolerance?
There is a distinction that needs to be made between food allergies and food
intolerance. Food allergies are true allergies and show the characteristic symptoms of
itching and skin problems associated with canine and feline allergies. Food intolerance
can result in diarrhea or vomiting and do not create a typical allergic response. Food
intolerance in pets would be similar to people that get diarrhea or an upset stomach from
eating spicy or fried foods. Fortunately, both food intolerance and allergies can be
eliminated with a diet free from offending agents.
Common food culprits
Several studies have shown that some ingredients are more likely to cause food
allergies than others. In order of the most common offenders in dogs are beef, dairy
products, chicken, wheat, chicken eggs, corn, and soy. As you may have noticed, the most
common offenders are the most common ingredients in dog foods. This correlation is not a
coincidence. While some proteins might be slightly more antigenic than others, many
proteins are similar in form and the incidence of allergic reactions are probably
associated with the amount of exposure. For example, pet foods have historically been made
up of beef, chicken, corn, and wheat. In an effort to combat food allergies, several
companies produced a diet made of lamb and rice. There was nothing special about
lamb and rice diets except those two ingredients were normally not present in pet foods.
Animals had not eaten lamb or rice before, and therefore, had not developed an allergy to
it yet. If the main ingredients in pet food become lamb and rice, then it would stand to
reason that the most common problem foods could become lamb and rice. The determinant of
whether a food is likely to cause a food allergy or not is based on the structure and size
of the glycoprotein in the food. In addition, many lamb and rice-based foods contain many
other ingredients, and if the animal has a food allergy to any of them, this lamb and rice
food will do nothing to treat the food allergy. In addition, while many people criticized
and blamed preservatives and flavorings as a source of food allergies, studies have shown
that they are not the causes, and while we may not have justifiable health concerns about
preservatives, food allergies is not one of them.
Symptoms
The symptoms of food allergies are similar to those of most allergies seen in dogs and
cats. The primary symptom is itchy skin. Symptoms may also include chronic
or recurrent ear infections, hair loss, excessive scratching, hot spots, and skin
infections that respond to antibiotics but reoccur after antibiotics are discontinued.
There is evidence that dogs with food allergies may sometimes have an increased incidence
of bowel movements. One study showed that non-allergic dogs have around 1.5 bowel
movements per day where some dogs with food allergies may have 3 or more per day.
It is difficult to distinguish an animal suffering from food allergies from an animal
suffering from atopy or other allergies based on physical signs. However, there are a few
signs that always make me suspect food allergies. One of these, is a dog with recurrent
ear problems, particularly yeast infections. Another, is a very young dog with moderate or
severe skin problems. A third tip off, is if a dog suffers from allergies year-round or if
the symptoms begin in the winter. And the final clue, is a dog that has very itchy skin
but does not respond to antihistamines or steroid treatment.
Diagnosis
The diagnosis for food allergies is very straightforward. But due to the fact that many
other problems can cause similar symptoms and that many times animals are suffering from
more problems than just food allergies, it is very important that all other problems are
properly identified and treated prior to undergoing diagnosis for food allergies. Atopy,
flea bite allergies, intestinal parasite hypersensitivity, sarcoptic mange, and
yeast or bacterial infections can all cause similar symptoms as food allergies. Once all
other causes have been ruled out or treated, then it is time to perform a food trial.
Elimination diets and provocative testing: A food trial
consists of feeding an animal a novel food source of protein and carbohydrate
for 12 weeks. A novel food source would be a protein and carbohydrate that the animal had
never eaten before. An example would be rabbit and rice, or venison and potato, or duck
and rutabagas. These are homemade diets but there are several commercial diets available
on the market. Pinnacle Brand (Breeders Choice is
MFG.) of either Duck and potato or Venison and potato. These 2 are
allergen free! No wheat, no chicken, turkey, or rice.. Regardless of the
diet used, it must be the only thing the animal eats for 12 weeks. This means no treats;
absolutely nothing but the special food and water. Young growing pets have special dietary
needs and a homemade diet that only contains one protein and one carbohydrate with no
multivitamin or fatty acid may not be suitable even for only twelve weeks. For puppies
undergoing a food trial, a balanced commercial diet like the ones listed above is
recommended.
