---
title: Anaphylaxis Emergency Protocol
description: A comprehensive clinical reference for the diagnosis and management of anaphylaxis in emergency settings.
keywords: [anaphylaxis, epinephrine, antihistamine, corticosteroid, airway management]
category: clinical
---

## Definition and Epidemiology

Anaphylaxis is a severe, life-threatening, generalized or systemic hypersensitivity reaction characterized by rapid onset of airway, breathing, and/or circulatory problems [1]. It is an acute, potentially fatal condition requiring prompt recognition and treatment. The estimated lifetime prevalence of anaphylaxis is 0.05-2% in the general population, with food, medication, and insect venom as the most common triggers [2].

## Diagnostic Criteria

The clinical diagnosis of anaphylaxis is based on the acute onset of symptoms involving the skin, mucosal tissue, or both, plus involvement of respiratory and/or cardiovascular systems, per the following criteria [1]:

1. Acute onset of illness with involvement of the skin, mucosal tissue, or both (e.g., generalized hives, pruritus or flushed, erythematous skin, angioedema)
   AND
2. At least one of the following:
   - Respiratory compromise (e.g., dyspnea, wheeze-bronchospasm, stridor, reduced peak expiratory flow, hypoxemia)
   - Reduced blood pressure or associated symptoms of end-organ dysfunction (e.g., hypotonia, collapse, syncope, incontinence)

## Initial Management

The cornerstones of anaphylaxis management are:

1. **Airway, Breathing, Circulation (ABC) Assessment and Stabilization**
   - Assess airway patency, provide supplemental oxygen, and be prepared to manage airway compromise with intubation or cricothyrotomy if necessary.
   - Assist ventilation with bag-valve-mask or other airway adjuncts as needed.
   - Assess and support circulatory status, including measurement of blood pressure and heart rate.

2. **Epinephrine Administration**
   - Epinephrine is the first-line treatment for anaphylaxis and should be administered immediately.
   - Dose: 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution) intramuscularly in the mid-outer thigh. Repeat every 5-15 minutes as needed.
   - Epinephrine is contraindicated in patients with known coronary artery disease, arrhythmias, or uncontrolled hypertension.

3. **Fluid Resuscitation**
   - Administer intravenous (IV) fluids, such as normal saline or lactated Ringer's, to maintain adequate perfusion and blood pressure.
   - Titrate fluid administration based on clinical response and hemodynamic parameters.

4. **Antihistamine and Corticosteroid Administration**
   - H1-antihistamines (e.g., diphenhydramine 25-50 mg IV) can be given to help manage cutaneous symptoms.
   - Corticosteroids (e.g., methylprednisolone 125 mg IV) may be administered to prevent biphasic reactions but should not delay epinephrine administration.

## Monitoring and Supportive Care

1. **Continuous Monitoring**
   - Monitor vital signs, oxygen saturation, and cardiac rhythm continuously.
   - Assess for signs of respiratory distress, hypotension, and end-organ dysfunction.

2. **Supplemental Oxygen**
   - Provide high-flow oxygen (6-15 L/min) via non-rebreather mask or other appropriate delivery device.

3. **Vasopressor Support**
   - If hypotension persists despite fluid resuscitation and epinephrine administration, consider additional vasopressor therapy (e.g., norepinephrine, dopamine).

4. **Bronchodilator Therapy**
   - For patients with bronchospasm, administer inhaled beta-agonists (e.g., albuterol) as needed.

## Disposition and Monitoring

1. **Observation Period**
   - Patients should be observed for at least 4-6 hours after the resolution of symptoms, as biphasic reactions can occur.
   - Longer observation (up to 24 hours) may be warranted for severe reactions, delayed presentation, or high-risk patients.

2. **Discharge Planning**
   - Patients who respond well to treatment and have no signs of ongoing reaction may be discharged home with instructions to fill and carry an epinephrine auto-injector prescription.
   - Educate patients on anaphylaxis recognition, avoidance of triggers, and proper use of epinephrine auto-injectors.
   - Refer patients to an allergist for further evaluation and management.

3. **Admission Criteria**
   - Patients with severe reactions, persistent symptoms, or comorbidities that increase the risk of complications should be admitted to the hospital for further monitoring and treatment.

## Special Considerations

1. **Anaphylaxis in Pregnancy**
   - Anaphylaxis in pregnancy is a medical emergency that requires prompt treatment, as it can have serious consequences for both the mother and the fetus.
   - Epinephrine should be administered without delay, and additional supportive measures, such as left uterine displacement, may be necessary.

2. **Anaphylaxis in Patients with Beta-Blocker or Angiotensin-Converting Enzyme (ACE) Inhibitor Therapy**
   - Patients taking beta-blockers or ACE inhibitors may have an increased risk of severe or refractory anaphylaxis.
   - These patients may require higher doses of epinephrine and additional supportive measures, such as glucagon administration.

3. **Anaphylaxis in the Perioperative Setting**
   - Anaphylaxis can occur during any stage of the perioperative period and requires immediate recognition and treatment.
   - The anesthesia team should be prepared to manage the airway, provide cardiovascular support, and administer epinephrine and other necessary medications.

In summary, anaphylaxis is a life-threatening condition that requires prompt recognition and aggressive management. The key principles of anaphylaxis treatment include airway stabilization, epinephrine administration, fluid resuscitation, and supportive care. Continuous monitoring and appropriate disposition are essential to ensure the best possible patient outcomes.

## References

1. Simons FER, Ardusso LRF, Bilò MB, et al. World Allergy Organization guidelines for the assessment and management of anaphylaxis. World Allergy Organ J. 2011;4(2):13-37.
2. Sampson HA, Muñoz-Furlong A, Campbell RL, et al. Second symposium on the definition and management of anaphylaxis: summary report--Second National Institute of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network symposium. J Allergy Clin Immunol. 2006;117(2):391-397.