Allergy Testing & Immunotherapy
ALLERGY TESTING
A test to determine what environmental allergens (pollens dusts insects and moulds but NOT FOOD) your pet reacts towards so we can design allergen immunotherapy to try to change the way their immune system responds to those allergens.
Blood, serum or saliva tests for food allergy are not useful.
In some cases we do intradermal (skin) testing by injecting dilute allergens into the top layer of the skin. We need to have dogs off drugs such as prednisone and antihistamines for a few weeks prior to this and they need to be sedated for the procedure. Apoquel, Atopica and Cytopoint (CADI) do not seem to interfere with skin testing.
If they cannot be off drugs easily or sedation carries more risk ( such as dogs with heart conditions or breathing problems) we may use a blood test.
There are 2 ways you can give allergen immunotherapy to your pet. The way we test does not limit this choice.
You should not do the test unless you plan to do immunotherapy for at least 18 months. You will need to keep managing their skin and allergies while we do immunotherapy as it takes a number of months to start to work and work better if symptoms are controlled. We are trying to retrain the immune system so it no longer overreacts to those allergens. Injectable allergens need to be kept in the fridge but sublingual do not. Most cat owners find it easier to give an injection once a week than something by mouth daily but we can do sublingual allergens in cats.
Allergen injections are given at home under the skin by the owners and have a 75 % chance of significantly decreasing the signs of allergic dermatitis after 12 months.
We start with three vials of different strengths and gradually increase the amount injected. There is a very small risk of serious reactions if the dose is increased too quickly but this is much lower than in humans and the schedule is less rigid.
Initially doses are given every 2 days but after a month they are usually given every 7 days long term. We wait 12 to 15 months before deciding if they have been helpful and you should plan on doing them for a number of years.
This initial set of vials lasts 3 months and each refill vials last 3 to 4 months.
Sublingual allergens are a glass vial with a small pump on top. The owner squirts a very small volume of liquid under their pet's tongue once a day every day. This is a newer method so we have less data. One early study suggested the success rate may a little less but the effect may be seen sooner than with injections. We have found compliance ( owners ability to actually give them reliably) has been better, especially in small dogs or owners who are not fond of needles.
Cost is about the same as injections for larger dogs but for dogs under 20 pounds they are slightly less expensive. Vials last about 20 weeks