Anaphylactic shock — also known as anaphylaxis — is a rapidly progressing, life-threatening allergic reaction that can occur within minutes or even seconds of exposure to a trigger. It requires immediate recognition and aggressive treatment to prevent respiratory collapse, cardiovascular failure, or death.
⚠️ What Is Anaphylactic Shock?
Anaphylactic shock is an acute, systemic IgE-mediated Type I hypersensitivity reaction, triggered by exposure to allergens such as:
- Drugs (e.g., penicillin, contrast media)
- Insect stings (e.g., bee, wasp)
- Foods (e.g., peanuts, shellfish, eggs, strawberries)
- Latex or chemicals
Upon exposure, mast cells release histamine, causing widespread vasodilation, airway swelling, hypotension, bronchoconstriction, and systemic urticaria.
🧬 Clinical Presentation of Anaphylaxis
Signs and symptoms typically appear within seconds to minutes of exposure and may include:
- Wheezing, bronchospasm, and laryngeal edema
- Cyanosis and shortness of breath
- Hypotension with reflex tachycardia
- Edema of lips, tongue, eyelids
- Generalized itching, urticaria, and flushing
- Nausea, vomiting, or diarrhea
- Altered mental status or collapse
Respiratory obstruction is the most fatal complication and must be treated immediately.
🚨 Emergency Management Protocol (ABC Approach)
1. Airway
- Assess for laryngeal edema or stridor
- Prepare for intubation if respiratory failure is imminent
- Provide 100% oxygen
2. Breathing
- Assist ventilation with bag-valve-mask if needed
- Nebulized bronchodilators (salbutamol) for bronchospasm
3. Circulation
- Position patient supine with legs elevated
- Begin IV fluids (normal saline bolus)
- Administer epinephrine 0.5 mg IM (repeat every 5 mins as needed)
- Epinephrine is preferred over norepinephrine due to bronchodilation effect
💊 Adjunctive Medications
- Chlorphenamine 10 mg IV
→ Antihistamine to block H1 receptors and reduce itching/urticaria - Hydrocortisone 200 mg IV
→ Steroid to suppress immune and inflammatory response - Salbutamol nebulization
→ If signs of asthma/wheezing persist - Aminophylline IV infusion
→ For bronchodilation in severe airway compromise
🏥 If Hypotension Persists
- Shift patient to ICU
- Start IV adrenaline infusion
- Continue fluids + vasopressors
- Monitor ECG continuously
📊 Additional Workup & Long-Term Considerations
- Serum tryptase level (within 1–6 hrs) to confirm mast cell activation
- Skin prick test before discharge to identify the allergen
- Prescribe oral antihistamines (e.g., chlorphenamine 4 mg q6h) if symptoms persist
- Educate patient on allergen avoidance and prescribe EpiPen (0.3 mg) for self-injection
❗ Important Note: If the patient is on beta-blockers, epinephrine may not work effectively. In such cases, consider IV salbutamol as a bronchodilator to prevent respiratory arrest.
✅ Summary
- Anaphylaxis is a medical emergency and demands rapid identification.
- ABC approach with airway protection and early epinephrine administration is crucial.
- If symptoms persist, escalate to IV adrenaline and ICU care.
- After recovery, teach self-care with EpiPen and identify allergens for future prevention.
Early action can save lives — always keep anaphylaxis on your differential when a patient collapses after allergen exposure.
