10/09/2026
It's Friday! Here's everything you need to know about potential allergy testing for your furry (and probably itchy) friend 🐾
Below, you can read more in-depth details about each form of testing.
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Q: What is allergy testing, and how does it work?
A: Allergy testing is performed to identify environmental allergens for allergen avoidance and for allergen specific immunotherapy. There are two forms of allergy testing, serum (blood) allergy testing, and intradermal (skin prick) testing.
1. Intradermal allergy testing is the gold standard for identifying environmental allergens in veterinary medicine, for both dogs and cats. This is because it is identifying the allergic reaction to the allergens in the end organ itself, the skin. The patients are sedated using reversible sedation (meaning that there is an antidote if the patient is too sleepy or not tolerating the sedation well). An area about the size of a post card is shaved on the side of the pet, behind the forearm. A grid of dots are drawn onto the pet, with each dot representing an allergen. A positive control (histamine), negative control (saline), and about 60 allergens are injected into the dermis using tiny needles. Then, the size, color, and turgidity of each wheal is measured in comparison to the positive and negative control to grade the allergic reaction on a scale of 1-4, with 4 being the same size as histamine, and 1 the same size as the saline. Patients with active skin infections should not undergo testing until the infection has resolved. A washout period of 1-2 weeks is recommended if a patient has been taking antihistamines or steroids.
2. Serum allergy testing is a blood test that measures allergen-specific Immunoglobulin E (IgE). This test is straight forward and non-invasive. However, it can be less sensitive than the Intradermal test. Chronic steroid administration prior to testing can suppress the test; otherwise, medications do not generally suppress the test. This test is preferred if sedation is risky for the patient (individuals with other diseases that make sedation risky, or breeds that may not tolerate sedation well, such as the brachycephalic (snub-faced) breeds).
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