Anaphylaxis

Anaphylaxis is a severe, potentially life-threatening allergic reaction that can occur within seconds or minutes of exposure to an allergen. This medical emergency requires immediate treatment with epinephrine and emergency medical care. Without prompt treatment, anaphylaxis can be fatal within minutes.

🚨 LIFE-THREATENING EMERGENCY

CALL 911 IMMEDIATELY if experiencing: difficulty breathing, swelling of face/throat, rapid pulse, dizziness, or severe whole-body reaction after allergen exposure. GIVE EPINEPHRINE IMMEDIATELY if available. Every second counts - anaphylaxis can be fatal within 15-30 minutes.

Medical Disclaimer: This information is for educational purposes only and should not replace professional medical advice. Always consult with a qualified healthcare provider for diagnosis and treatment of any medical condition.

Emergency Response Steps

  1. Call 911 immediately
  2. Give epinephrine auto-injector if available:
    • Remove from carrier tube
    • Remove safety cap
    • Press firmly into outer thigh (through clothing if needed)
    • Hold for 3-10 seconds
    • Massage injection site for 10 seconds
  3. Lay person flat (elevate legs if possible)
  4. If pregnant, lay on left side
  5. Remove allergen if still in contact
  6. Loosen tight clothing
  7. If no breathing, begin CPR
  8. Give second dose of epinephrine after 5-15 minutes if no improvement
  9. Stay with person until emergency help arrives

Recognizing Anaphylaxis

Anaphylaxis typically involves two or more body systems and develops rapidly:

Respiratory Symptoms

  • Upper airway:
    • Swelling of lips, tongue, throat
    • Hoarse voice
    • Difficulty swallowing
    • Stridor (high-pitched breathing)
  • Lower airway:
    • Shortness of breath
    • Wheezing
    • Coughing
    • Chest tightness

Cardiovascular Symptoms

  • Rapid, weak pulse
  • Low blood pressure
  • Dizziness or lightheadedness
  • Loss of consciousness
  • Cardiac arrest
  • Pale or blue skin color

Skin Symptoms

  • Hives (urticaria)
  • Flushing or redness
  • Swelling (angioedema)
  • Itching
  • Warmth

Gastrointestinal Symptoms

  • Nausea
  • Vomiting
  • Abdominal cramps
  • Diarrhea

Other Symptoms

  • Sense of impending doom
  • Anxiety
  • Confusion
  • Metallic taste
  • Uterine cramps in women

Common Triggers

Foods (Most Common in Children)

  • Top allergens:
    • Peanuts
    • Tree nuts (almonds, cashews, walnuts)
    • Fish
    • Shellfish
    • Milk
    • Eggs
    • Soy
    • Wheat
    • Sesame

Medications (Most Common in Adults)

  • Antibiotics (penicillin, cephalosporins)
  • Aspirin and NSAIDs
  • Anesthetics
  • Radiocontrast media
  • Opioids
  • Vaccines (rare)

Insect Stings/Bites

  • Honeybees
  • Wasps
  • Hornets
  • Yellow jackets
  • Fire ants

Other Triggers

  • Latex: Gloves, balloons, condoms
  • Exercise: Exercise-induced anaphylaxis
  • Cold: Cold-induced anaphylaxis
  • Idiopathic: No identifiable trigger (20% of cases)

What Happens During Anaphylaxis

  1. Allergen exposure: Through ingestion, injection, inhalation, or skin contact
  2. IgE antibody activation: Triggers mast cells and basophils
  3. Mediator release: Histamine, tryptase, leukotrienes, prostaglandins
  4. Systemic effects:
    • Vasodilation → hypotension
    • Increased vascular permeability → swelling
    • Smooth muscle contraction → bronchospasm
    • Increased mucus production
  5. Shock state: Inadequate tissue perfusion

Diagnosis

Clinical Criteria

Anaphylaxis is likely when ONE of the following occurs:

  1. Acute onset with skin/mucosal involvement AND:
    • Respiratory compromise OR
    • Reduced blood pressure/collapse
  2. Two or more of the following after allergen exposure:
    • Skin-mucosal symptoms
    • Respiratory compromise
    • Reduced blood pressure
    • Persistent GI symptoms
  3. Reduced blood pressure after known allergen exposure

Laboratory Tests

  • During reaction:
    • Serum tryptase (peaks 60-90 min)
    • Plasma histamine (peaks 5-10 min)
  • After recovery:
    • Specific IgE testing
    • Skin prick testing
    • Component testing
    • Challenge testing (controlled setting)

Medical Treatment

First-Line Treatment

  • Epinephrine (adrenaline):
    • ONLY proven life-saving treatment
    • IM injection: 0.3-0.5mg adults, 0.15mg children
    • Repeat every 5-15 minutes if needed
    • No absolute contraindications

Supportive Treatment

  • Airway management:
    • High-flow oxygen
    • Intubation if needed
    • Cricothyrotomy for complete obstruction
  • Circulation support:
    • IV fluids (1-2L rapidly)
    • Vasopressors if hypotensive
    • Cardiac monitoring

Second-Line Medications

  • H1 antihistamines: For hives and itching
  • H2 blockers: May provide additional benefit
  • Corticosteroids: May prevent biphasic reactions
  • Bronchodilators: For persistent bronchospasm
  • Glucagon: For patients on beta-blockers

Observation Period

  • Minimum 4-6 hours for resolved symptoms
  • 8-24 hours for severe reactions
  • Watch for biphasic reactions (up to 20% of cases)

Prevention and Management

Allergen Avoidance

  • Read all food labels carefully
  • Ask about ingredients when eating out
  • Avoid cross-contamination
  • Wear medical alert identification
  • Inform healthcare providers of allergies
  • Check medications for allergens

Emergency Preparedness

  • Always carry epinephrine:
    • Two auto-injectors recommended
    • Check expiration dates
    • Store at room temperature
    • Replace if discolored
  • Written action plan:
    • List of allergens
    • Signs and symptoms
    • Emergency contacts
    • Treatment steps

Education

  • Train family, friends, and caregivers
  • Practice using trainer auto-injectors
  • Educate about cross-reactivity
  • School/workplace emergency plans
  • Regular refresher training

Immunotherapy

  • Venom immunotherapy: 95% effective for insect stings
  • Food immunotherapy: Emerging treatments (peanut, egg, milk)
  • Drug desensitization: When medication is essential

Special Considerations

Children

  • Food allergies most common trigger
  • May present with behavioral changes
  • Epinephrine dosing by weight
  • School action plans essential
  • Age-appropriate education

Elderly

  • Medications most common trigger
  • Cardiovascular symptoms predominate
  • Higher mortality risk
  • Consider medication interactions

Pregnancy

  • Epinephrine remains first-line treatment
  • Position on left side
  • Monitor fetal heart rate
  • Prepare for emergency delivery if needed

Prognosis and Outcomes

With prompt treatment, most people recover completely from anaphylaxis:

  • Fatal anaphylaxis: 0.7-2% of cases
  • Death usually within 30 minutes for food, 15 minutes for venom, 5 minutes for medications
  • Delayed epinephrine increases mortality risk
  • Biphasic reactions occur in up to 20%
  • Most deaths preventable with timely epinephrine

Long-term Management Success

  • Proper education reduces risk
  • Carrying epinephrine saves lives
  • Most can manage condition effectively
  • Quality of life maintained with precautions
  • Anxiety manageable with support