The intra-dermal test simply means a dog allergy skin test
In simplest terms small amounts of the possible allergens are injected under the skin of the dog. The reaction, is graded and a decision is made if the dog is allergic to that specific allergen. Note this is exactly the same as they do with humans when you get tested for allergies. The main trick is getting a dog to sit still, and the interpretation of the reaction. A reaction is considered to have occurred it a lump or discoloration occurs around the injection point.
This sounds fairly simple, but with the mass of different allergens that a dog cold be allergic to and the variations in one class such as mold, it is not always easy to get a clear result.
dog allergy Rules before allergen injection
To get the truest reaction a dog must be clear of the drugs that will mess with the results, and in particular be clear of the kinds of drugs given to an allergy dog. In particular:
- off of oral cortisone medication for at least 1 month before testing.
- inject able cortisone up to two months since last injection
- a few days off tranquilizers at the time of testing
- No antihistamine medication for 10 days.
Noting that when a dog is suffering an allergy it is usually given some kind of cortisone to reduce the swelling around the allergy site. Tranquilizers are often used by vets to reduce the obsessive itching and claws breaking the skin making an allergy worse.
Antihistamines are at the forefront of calming human an dog skin allergies down – hence during grass season and spring dogs can be placed on these for moths just like their owner
the actual Intradermal (skin) Test method for diagnosis
Usually a sedative (not tranquiler) is given to calm the dog down and to minimize the release of cortisone due to stress. So neither natural or vet cortisone can be present otherwise it will mask the swelling
The dog hair is clipped at a site where there is not obvious current dermatitis.
A rectangular area of skin is marked with a pen in a matrix and a score card with corresponding cells is ready for the results.
A small amount of histamine is injected into a site near the matrix. There should be some reaction to the histamine – since this is what is occurring inside of the dog’s body. That is the dog releases large amounts of histamine chemical as an over reaction to a believed allergen which starts the chain of events of the dog allergy. If the dog has no reaction to histamine being used before the test, then it is likely that it wont react to any of the allergens injected and the test will be of no use.
Reaction times vary from allergen and dog to dog, but essentially recording some kind of negative reaction at the site of the injected allergen will give a vet a strong indication of what allergens the dog is most likely suffering from, so that action plans can be made – ie avoidance or other techniques.