Lee: The common response is to reach for diphenhydramine and dexamethasone, along with supportive care. Those medications aren’t \u201cwrong,\u201d but they don’t address the immediate, life-threatening pathophysiology. The critical drug that\u2019s missing is epinephrine. If you could give one medication, what would that be? It is epinephrine. Think of it this way: For a person with a severe allergy, what do they carry? An EpiPen. It\u2019s not a DexPen or a Benadryl pen. It\u2019s an EpiPen. That\u2019s the direct counter to the systemic vasodilation and bronchoconstriction happening during anaphylaxis.<\/p>\n
dvm360: You stress the importance of differentiating between hypersensitivity types. Why is that so crucial for practice?<\/p>\n
Lee: Because the management and long-term strategy for each type is remarkably different. We need to differentiate type one through 4 reactions. In practice, you might see:<\/p>\n
Type I: The immediate anaphylaxis we just discussed.Type II: Immune-mediated reactions, like IMHA or thrombocytopenia.Type III: Immune-complex reactions, which can look like a localized vasculitis or little bald spots at the injection site.Type IV: Delayed-type hypersensitivity, which can cause sterile granulomas or lumps.<\/p>\n
Understanding which pathway you\u2019re dealing with is essential for everything from your acute treatment to your plan for future vaccinations for that patient.<\/p>\n
dvm360: Beyond emergency treatment, you\u2019ve identified a common error in vaccine administration protocol itself. What are you seeing?<\/p>\n
Lee: This is a widespread issue that started with a good intention. Decades ago, the concern over feline injection-site sarcomas rightly led to the protocol of giving feline vaccines very low on the body. However, that feline-specific protocol is now being incorrectly applied to dogs. I’m seeing a lot of people putting canine vaccines low on the limbs, and that is problematic. It is not helping out the pet; in fact, it’s working against us.<\/p>\n
dvm360: What is the correct approach for vaccine sites?<\/p>\n
Lee: For cats, keep everything low; for dogs, keep everything high. Administering vaccines high on the body in dogs is a lot more comfortable for the patient, and you’re going to have fewer problems.<\/p>\n