Anaphylaxis Symptoms and Diagnosis

In an emergency situation, your doctor will quickly diagnose anaphylaxis according to visible symptoms and immediately treat you.

This is because time is of the essence, and it would be a risk to your life to try to confirm an anaphylactic reaction with lab tests before administering treatment.

A rapid diagnosis of anaphylaxis is made on the basis of one of two scenarios.

• Respiratory symptoms such as shortness of breath, wheezing, low blood oxygen levels, or persistent cough or throat-clearing
• Hypotension, or low blood pressure
• Symptoms that indicate your organ function is impaired, for example your muscles are soft and flabby, you’re fainting, or incontinent

• Symptoms affecting your skin such as rash, hives, itchiness, reddening of the skin, or swelling of the face, lips, tongue, or uvula
• Respiratory symptoms such as shortness of breath, wheezing, low blood oxygen levels, or persistent cough or throat-clearing
• Hypotension 
• Gastrointestinal symptoms such as vomiting or painful cramps

When possible, it’s important to make sure your symptoms aren’t caused by another condition if they don’t clearly indicate anaphylaxis. That’s because another condition may also require urgent treatment, and could be made worse by anaphylaxis treatment.

• Generalized hives or swelling
• Shock caused by cardiovascular issues (cardiogenic or hypovolemic shock)
• Fainting (due to nonallergic factors)
• Certain endocrine problems (carcinoid syndrome or pheochromocytoma)
• Foreign object stuck in the airway
• Pulmonary embolism (a blood clot in the lungs)
• Autonomic epilepsy or seizure disorder
• Stroke
• Drug overdose
• Monosodium glutamate or sulfite ingestion
• Reaction to vancomycin infusion
• Leukemia
• Flushing syndromes
• Vocal cord dysfunction
• Panic attack

The list of possible conditions that share the symptoms of anaphylaxis would be in the hundreds, says Torbati. But, “most of the time it’s not a difficult diagnosis. If the history is there, like an insect bite or an exposure to a known allergen, diagnosis becomes simple.”

After emergency care for anaphylaxis, it’s a good idea to follow up with an allergist who can evaluate your risk of anaphylaxis generally and help figure out whether any previous symptoms were related to the condition. Your doctor will investigate all potential causes of your symptoms. This may involve allergy tests as well as tests for other health conditions.

Additional reporting by Nina Wasserman.