Dog Allergy Test: The Blood Work & Skin Test

A dog allergy test refers to both the blood work and the Intradermal Skin Test (IDST) which is the diagnostic testing done before administering allergy shots for dogs. These tests and the arrangement of allergy shots are the domain of the veterinary dermatologist who is a specialist in the diagnosis and treatment of allergies in animals. In the United States, veterinary dermatologists should have board certification of the American College of Veterinary Dermatology (ACVD). It is best to have the dog allergy test performed during the season when the allergies are at their worst.

House Cleaning Prior to Dog Allergy Testing

Before going to a vet dermatologist for dog allergy testing and allergy shots for dogs it is very desirable to try one last at-home procedure in a final attempt to stop the allergenic reactions your dog is enduring. Surprisingly, this procedure sometimes works wonders.

Temporarily remove the dog from the home so the house environment can be thoroughly cleaned without the dog being present. This may mean several days at a boarding facility or at a relative or friend’s home. The house cleaning should be a very thorough cleaning, like a major spring cleaning where everything is completely cleaned and aired out. A HEPA air purifier can be introduced into the house to better remove air impurities and airborne allergens, if you don’t already have one. When the cleaning is complete and the dog is again living back in your house, it is possible his or her dog allergies symptoms may be substantial reduced or possibly eliminated. If this is the case, then the home environment can be controlled so the allergy symptoms can be greatly eased. This is good news. However, if there is little or no change in dog allergies symptoms then depending upon circumstances it may be best to proceed with dog allergy desensitization (allergy shots).

Your Veterinarian

Your veterinary dermatologist will expect your family vet has already conducted a comprehensive workup to rule out other possible causes of skin irritation, such as fungal or bacterial infections and other medical conditions, such as hypothyroidism before sending the dog to the vet dermatologist. However, sometimes in obviously difficult cases, a vet may send a dog immediately to a veterinary dermatologist for all preliminary testing. If this is the case, then your vet dermatologist will perform the tests just mentioned before the following pre-allergy shot diagnostic testing.

Pre-Allergy Shot Diagnostic Testing

Before dog allergy shot therapy can begin, a full medical history is taken along with diagnostic tests, which include blood work and a skin scratch test. This is done to establish an accurate diagnosis of the allergy and exact allergen identification. This dog allergy test is very important as the allergy shot vaccine will be based on these results.

1. Blood Work testing will check for antigen-induced antibodies in the blood of the dog. The old standard is the radioallergosorbent test (RAST). However, many vets now prefer the enzyme-linked immunosorbent assay test (ELISA). ELISA is similar to RAST but ELISA is usually more accurate and is the one normally recommended. In essence, blood is drawn and is sent to the lab. The lab may be able to identify allergens. It is more accurate in identifying inhalant allergens than food or contact allergens. Unfortunately, testing usually will take several weeks. The accuracy of results can be a problem as false positives may be evident. Therefore, blood tests are less favored except when a skin test is not possible. Circumstances when blood tests may be desirable also include when the dog has skin infection, the allergy condition is especially serious, a skin test was negative when atopy is still suspected, the dog is too young for skin testing, or the number of suspect allergens are many. Of course there can be other circumstances.

2. The Intradermal Skin Test (IDST), or skin scratch test, is usually the most important dog allergy test. The dog is put to sleep in order to avoid any distress to the animal. An area on the dog is prepared (shaved), usually an upper or lower arm, the upper back or a side. Within a grid layout, the skin is scratched or injected with the most likely, common, or suspected allergens. Within several hours redness and swelling may become evident, thus identifying the allergen or allergens. However, in this dog allergy test identification is a bit of an art and it does take experience to determine accurate results (which is why you are paying for a specialist).

With allergens identified, sometimes another test may be able to discover more allergens. With the dog allergy test complete, a determination will be made whether or not allergy shots are appropriate. See the next article, Allergy Shots for Dogs.