Anaphylactic shock is not particularly difficult to diagnose. However, it is essential that treatment begin before formal diagnostic efforts are made, because timely treatment is the most important factor in whether affected animals will survive.
Virtually all cases of anaphylactic shock are diagnosed based only on history and physical examination. Treatment must begin immediately, if not sooner, if a dog experiencing an anaphylactic episode is going to have a fighting chance of recovery. Once the animal is stabilized and hospitalized, most veterinarians will monitor blood pressure regularly, perform a urinalysis and draw blood samples for a complete blood count and serum chemistry panel. The results of these tests are usually unremarkable if anaphylaxis is the only condition affecting the dog. Chest radiographs (x-rays) may be recommended if the dog is having severe difficulty breathing, to assess whether primary pulmonary (lung) disease is causing or contributing to the respiratory distress.
Anaphylaxis should always be suspected if a dog experiences an extremely sudden and severe onset of cardiovascular (heart and blood vessels) and respiratory (lungs) collapse. This condition can cause death within as little as one hour from exposure to the inciting agent.