02/08/2026
Life-threatening allergic reactions look different in dogs.
People having a severe allergic reaction develop airway swelling and difficult breathing. Dogs almost never show those symptoms. Instead, vomiting, bloody diarrhea, and weakness can mean serious anaphylaxis.
Testing may show acute liver injury, bleeding into the abdomen, and fluid in the wall of the gallbladder (a gallbladder "halo").
Prompt, aggressive treatment with epinephrine (the stuff in EpiPens), steroids, anti-histamines, and fluids is critical to stop the reaction and relieve signs of shock.
Fortunately, dogs who are diagnosed quickly and treated correctly have a very good prognosis and do well. Untreated anaphylaxis, though, can be fatal.
Any pet experiencing vomiting should be checked out by a Vet immediately. While it doesn't seem intuitive to investigate an allergic reaction with ultrasound, the information we gather can save a life.