What should be covered in a paramedic class on allergic reactions?

Paramedic Class Outline: Allergic Reactions

A comprehensive paramedic class on allergic reactions should focus primarily on rapid recognition and treatment of anaphylaxis, as this represents the most life-threatening allergic emergency. 1, 2

I. Introduction to Allergic Reactions

A. Pathophysiology

• Definition of allergic reactions: IgE-mediated immune responses to foreign proteins (allergens) 3
• Mechanism: allergen aggregation of IgE molecules on mast cells and basophils leading to mediator release 3
• Distinction between allergic (IgE-dependent) and anaphylactoid (IgE-independent) reactions 1
• Role of histamine, prostaglandins, and cytokines in causing vasodilation, bronchospasm, and capillary leakage 4

B. Epidemiology

• Incidence of anaphylaxis: 2.1 per 1,000 person-years in the US 5
• Most anaphylactic reactions occur outside hospital settings 5
• Increasing emergency department visits for anaphylaxis, especially among children 6

C. Risk Factors for Severe Reactions

• Coexisting asthma
• Mast cell disorders
• Older age
• Underlying cardiovascular disease
• Peanut and tree nut allergies
• Drug-induced reactions 5
• Delayed epinephrine administration 6

II. Common Triggers of Allergic Reactions

A. Age-Related Patterns

• Children: predominantly food allergies 4
• Adults: medications and insect stings 4

B. Specific Triggers

• Medications (most common overall trigger)
• Stinging insect venoms
• Foods (especially peanuts, tree nuts, fish, shellfish, milk, and eggs)
• Latex
• Exercise
• Idiopathic (unknown cause in up to 20% of cases) 1, 5

III. Clinical Presentation and Assessment

A. Classification of Severity

• Grade I: Skin and mucosal signs (generalized erythema, urticaria, angioedema)
• Grade II: Moderate multi-organ involvement (skin/mucosal signs plus moderate hypotension, tachycardia, moderate bronchospasm, or GI symptoms)
• Grade III: Life-threatening mono- or multi-organ involvement (severe hypotension, tachycardia/bradycardia with arrhythmia, severe bronchospasm)
• Grade IV: Cardiac or respiratory arrest 1

B. Signs and Symptoms by System

1. Cutaneous (most common)

   • Urticaria (hives)
   • Angioedema
   • Flushing
   • Pruritus

2. Respiratory

   • Dyspnea
   • Bronchospasm
   • Stridor
   • Laryngeal edema
   • Upper airway obstruction

3. Cardiovascular

   • Hypotension
   • Tachycardia
   • Arrhythmias
   • Shock
   • Cardiac arrest

4. Gastrointestinal

   • Nausea/vomiting
   • Abdominal cramps
   • Diarrhea 1, 7

C. Differential Diagnosis

• Vasovagal reactions
• Panic attacks
• Vocal cord dysfunction
• Asthma exacerbation
• Carcinoid syndrome
• Mastocytosis
• Hereditary angioedema 1

IV. Emergency Management of Anaphylaxis

A. Initial Assessment and Approach

• Rapid assessment of ABCs (Airway, Breathing, Circulation)
• Recognition of anaphylaxis using National Institute of Allergy and Infectious Disease criteria 6
• Removal of trigger if possible 5

B. First-Line Treatment

• Epinephrine is the first-line treatment for anaphylaxis and should be administered immediately at the onset of symptoms 1, 2, 5
• Route: Intramuscular (IM) in anterolateral thigh
• Adult dosing: 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution)
• Pediatric dosing:

  • 12 years: 500 μg (0.5 mL of 1:1000)

  • 6-12 years: 300 μg (0.3 mL of 1:1000)
  • <6 years: 150 μg (0.15 mL of 1:1000) 2
• May repeat every 5-15 minutes if symptoms persist 2

C. Airway Management

• Position patient appropriately (supine with legs elevated if hypotensive)
• Administer high-flow oxygen (100%)
• Prepare for advanced airway management if needed
• Monitor for signs of upper airway obstruction 2

D. Circulatory Support

• Establish IV access with large-bore catheter
• Administer fluid bolus (0.9% saline or Ringer's lactate)
• Adult: 1-2 L rapidly
• Pediatric: 20 mL/kg bolus 2

E. Second-Line Medications

• Antihistamines (after epinephrine administration):

  • Diphenhydramine (H1 blocker): Adults 25-50 mg IV/IM; Children 1 mg/kg (max 50 mg) 8
  • H2 blockers (ranitidine, famotidine) may provide additional benefit

• Corticosteroids (to prevent biphasic reactions):

  • Methylprednisolone: Adults 125 mg IV; Children 2 mg/kg
  • Hydrocortisone: Adults 200 mg IV; Children 6-12 years 100 mg; <6 years 50 mg 2

• Bronchodilators:

  • Albuterol nebulizer for bronchospasm 2

F. Refractory Anaphylaxis Management

• IV epinephrine infusion for persistent hypotension
• Alternative vasopressors (norepinephrine, vasopressin)
• Glucagon for patients on beta-blockers 2, 5

V. Post-Emergency Care and Monitoring

A. Observation Period

• Monitor for biphasic reactions (recurrence without re-exposure)
• Observation period: 4-12 hours depending on risk factors
• Longer observation for severe reactions or those requiring multiple epinephrine doses 5

B. Patient Education and Discharge Planning

• Prescription for epinephrine auto-injector
• Training on auto-injector use
• Written emergency action plan
• Medical identification jewelry
• Referral to allergist 1, 5

VI. Special Considerations

A. Pediatric Considerations

• Age-appropriate dosing for medications
• Pediatric equipment availability
• Family education 1

B. Pregnant Patients

• Position to avoid aortocaval compression
• Same medication priorities as non-pregnant patients

C. Elderly Patients

• Higher risk for severe reactions
• Consider comorbidities and medication interactions

VII. Practical Skills Training

A. Epinephrine Administration

• Auto-injector demonstration and practice
• Manual drawing and administration from ampules/vials
• Proper IM injection technique

B. Airway Management Skills

• Basic airway positioning
• Bag-valve-mask ventilation
• Advanced airway techniques for severe reactions

C. Vascular Access

• IV/IO access techniques
• Fluid administration

D. Scenario-Based Training

• Recognition scenarios with varying presentations
• Full management simulations
• Team-based approach

VIII. EMS System Integration

A. Communication with Dispatch

• Key information to relay
• Pre-arrival instructions

B. Transport Considerations

• Appropriate receiving facility selection
• Continued monitoring during transport
• Preparation for deterioration

C. Documentation Requirements

• Critical elements to document
• Timing of interventions
• Response to treatments

IX. Quality Improvement

• Case review process
• Performance metrics for anaphylaxis management
• System improvement strategies

X. Prevention Strategies

• Community education on allergen avoidance
• School and public venue preparedness
• Public access to epinephrine programs

This comprehensive outline covers the essential components needed for paramedics to effectively recognize and manage allergic reactions, with special emphasis on life-threatening anaphylaxis.