Anaphylaxis Diagnosis and Management

Immediate Life-Threatening Consideration: Anaphylaxis

The American Heart Association and the American Academy of Pediatrics recommend that the combination of facial swelling, shortness of breath, and anxiety represents anaphylaxis until proven otherwise and requires immediate emergency response system activation and epinephrine administration if available 1, 2
Anaphylaxis is the primary diagnosis that must be ruled out when these three symptoms present together, with clinical criteria including acute onset and involvement of skin/mucosal tissue and respiratory compromise 1, 2
Facial swelling combined with respiratory symptoms defines anaphylaxis by established diagnostic criteria, with shortness of breath manifesting as dyspnea, wheeze/bronchospasm, or sensation of throat closing 1, 2
Anxiety is a direct consequence of the life-threatening nature of anaphylaxis and the sensation of impending doom 1

The American Heart Association recommends activating the emergency response system immediately and administering epinephrine 0.3 mg intramuscularly in the lateral thigh for adults (0.15 mg for children 15-30 kg) if an autoinjector is available 1, 2, 4
Epinephrine prevents or decreases upper airway mucosal edema, prevents hypotension, and provides bronchodilation for respiratory symptoms 2
Delayed epinephrine administration is associated with increased risk of poor outcomes, including death 2
If no response to initial epinephrine dose and EMS arrival exceeds 5-10 minutes, consider repeat dose 1

The American Academy of Allergy, Asthma, and Immunology notes that isolated angioedema without other systemic features may cause facial swelling and anxiety about breathing, but true shortness of breath suggests progression to anaphylaxis requiring epinephrine 1, 2
Facial swelling-erythema over an involved sinus with respiratory symptoms suggests complicated sinusitis, requiring urgent evaluation for complications 5

The American Heart Association and the American Academy of Pediatrics recommend immediately assessing for anaphylaxis criteria, obtaining rapid exposure history, and not waiting for complete symptom evolution 1, 2
Early epinephrine is associated with better outcomes, and anxiety in this context is a symptom, not a diagnosis 1, 2

The American Heart Association recommends not delaying epinephrine while obtaining IV access or waiting for antihistamines, and avoiding subcutaneous epinephrine 1, 2
Do not assume resolution after initial improvement, as biphasic reactions can occur, requiring observation and possible repeat epinephrine 1