Food
Allergy
Dogs are not likely to be born with food allergies. More commonly,
they develop allergies to food products they have eaten for a long
time.
The most common sign of food allergy is inflamed, itchy skin, usually
around a dog’s feet, face, ears, armpits, and groin. However, food
allergy may produce itching, digestive disorders, respiratory distress,
scratching at ears, shaking the head, licking and biting at the
hind quarters or feet, rubbing faces on carpeting, ear inflammations,
coughing, and rarely vomiting, diarrhea, flatulence, sneezing, asthma
like symptoms, behavioral changes, seizures, gagging, and vomiting,
loss of appetite, head shaking, and hair loss.
Any
food or food ingredient can cause an allergy. Generally the protein
component from the meat source such as beef, pork, chicken, horsemeat,
or turkey is the most likely offender. Dogs can become allergic
to milk, fish, eggs, corn, wheat, soy, artificial sugars and chemical
preservatives.
Most
vets test for food allergy when the clinical signs have been present
for several months, when the dog has a poor response to steroids,
or when a very young dog itches without other apparent causes of
allergy. Testing is done with a special hypoallergenic diet.
Because
it takes at least 8 weeks for all other food products to get out
of the system, the dog must eat the special diet exclusively for
two to three months (or more). When trying to isolate a food allergen,
the dog must not get anything but the prescribed diet in order for
it to be a successful test.
After
a dog is put on a special diet, if any types of table food, snacks
and treats, table scraps, vitamins or other pet foods are normally
given to the dog, they must be discontinued during the testing period.
There may be problems with certain types of chewable heartworm preventative,
as well.
Your
vet will instruct you on how to proceed if a positive response occurs.
If
the dog tolerates the food well and the symptoms decline or disappear,
other foods can be gradually reintroduced to determine which ingredient
is the culprit. If the symptoms are not alleviated in four weeks,
another hypoallergenic diet can be tried, and if it is not successful,
further diagnostic tests are indicated.
Although
tests for food allergy are available, the reliability of the test
is so low that it is not recommended at this time. A food trial
remains the best diagnostic test for food allergy.
Commercial
dog foods can be found that do not contain the offending allergen.
Because
dogs that are being tested for inhalant allergy generally itch year
round, a food allergy dietary test can be performed while the inhalant
test and antigen preparation are occurring.