Diagnosing a Canine Allergy with an Intradermal Skin Test

A canine allergy problem can be caused by one of three culprits: fleas, food or environment. If your dog is still showing symptoms after being treated for flea and food allergies, he has environmental allergies. A skin test can help determine which allergens are affecting your dog and develop a vaccine to reduce symptoms.

Types of Tests

There are two ways to test which environmental allergens are affecting your pet: blood test and intradermal skin test.

Blood tests check for antigen-inducing antibodies in the dog's blood. This is an effective test, but it was designed for humans, which respond to allergens different from dogs so you may get a false positive from the test. Results generally take weeks, but blood tests can be used when intradermal testing can't such as if the dog is too young, the skin is too irritated or the dog is sensitive to anaesthesia.

Though blood tests are more common, intradermal skin tests are considered the gold standard in allergy testing. A patch of the dog's skin is shaved so antigens can be inserted into the skin. After a few hours, the skin patterns are observed to see which antigens caused a reaction.

Value of Intradermal Skin Tests

The intradermal skin test is best done with a professional canine dermatologist because reading the test requires significant skill. The antigens are arranged in a particular pattern that allows for easier identification, but it can still be difficult to determine which is causing the reaction and if the reaction is significant.

When read correctly, skin tests lead to 75 percent accuracy in determining the appropriate antigens. The tests work best if performed when allergies are at their worst.

Once allergens are identified, a vaccine can be prepared. The vaccination is made up of a diluted concentration of all the allergens that caused a reaction during the skin test. The vaccination must be given consistently for weeks or months as your dog builds up immunity to the allergens. After he builds his immunity, he will only need an occasional booster. When his body is immune to the allergens, he will no longer exhibit the symptoms.

Concerns of Intradermal Skin Tests

To conduct the intradermal skin test, your pet must be put under mild anaesthesia. This is dangerous for young dogs, dogs with short nasal passages such as pugs and bulldogs or dogs that have shown a sensitivity.

To properly conduct this test, your dog must not take steroids or antihistamines for several weeks. If his symptoms are so severe that this isn't possible, skin testing will not be effective.

If your veterinarian is not an expert at reading such tests or doesn't offer the vaccine as a treatment option, this is a waste of money because there is no way to remove environmental allergens from your dog's environment completely.

These test are generally not though to be effective for food allergies.

If your dog has allergies that last longer than four months and don't respond to traditional treatment, he may benefit from an intradermal skin test and vaccination protocol. Seek out a certified canine dermatologist to begin a treatment, which could reduce your dog's symptoms and help him live a healthier life.