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Allergic Reaction

Recognize

  • Itching, hives, flushing, angioedema
  • Coughing, wheezing, stridor, or respiratory distress
  • Chest or throat constriction
  • Difficulty swallowing
  • Difficulty phonating
  • Nausea / vomiting
  • Altered Mental Status
  • Hypotension or shock
  • Edema

Evaluate

  • Onset and trajectory of symptoms
  • Anatomic and situational location of exposure
  • Insect sting or bite
  • Known allergies: food, environmental, medication, other
  • Known or suspected exposure: past occurrences and current event
  • Known history of sensitivity or allergic reaction
  • Past medical and medication history
  • New clothing, soap, or detergent
  • New medications
 

Administer Treatment

  • Remove allergy trigger if known and present
  • Prioritize interventions based on clinical presentation and severity of reaction
  • Supplemental oxygen PRN for goal SpO2
  • Attentive and prompt airway assessment and management
     Airway Management if indicated per Airway Management PCG (P1)
  • If patient has suspected or known exposure and exhibits signs of any: respiratory distress, airway
    restriction, altered mental status or shock, treat accordingly
      • Epinephrine Auto-Injector 0.3 mg IM if available
      • Vascular access per Vascular Access PCG (P33)
      • Consider crystalloid fluid bolus 500 mL IV/IO to support hemodynamics, repeat PRN
      • Diphenhydramine (Benadryl) 50 mg IM/IV/IO
      • Epinephrine (1mg/1mL) 0.3 mg IM or Epinephrine (1mg/10mL) 0.1 mg IV/IO q 3 min PRN for
        MORE SEVERE REACTION
          • Consider Epinephrine infusion 0.01 mcg/kg/min IV/IO, titrate to max 0.1 mcg/kg/min
            as an alternative to repeat IM or IV/IO doses
          • Monitor ECG rhythm closely, Epinephrine may potentiate arrhythmias, especially in
            patients over the age of 40
      • Methylprednisolone (Solu-Medrol) 125 mg IV/IO
      • Albuterol (2.5 mg/3 mL) nebulized for wheezing or shortness of breath
 

Consider Differentials

  • Urticaria
    (rash only)
  • Anaphylaxis (severe systemic effect)
  • Shock (severe vascular effect)
  • Angioedema (drug induced or infection)
  • Aspiration / airway obstruction
  • Vasovagal event
  • Asthma or COPD
  • Infection (ex: retropharyngeal abscess, bacterial tracheitis, croup, epiglottitis, strep)
  • Pulmonary edema or CHF
  • Metabolic disorders

    • Transport Considerations

  • During
    transport, maintain astute airway, breathing, circulation and mental status assessment with
    prompt intervention as needed. Stability can quickly change to instability in these patients.
  • Consider early airway management, reference Airway Management PCG (P1)

    • Information

  • Typically,
    the shorter the interval from exposure to symptoms, the more severe the reaction
  • Hemodynamic instability may recur up to 24 hours after initial stabilization

    • Other Populations

  •  
    Neonatal/ Pediatric drug dosing:
      • Pediatric Epinephrine Auto-Injector JR dose is 0.15 mg for patients 15-30 Kg
      • Diphenhydramine (Benadryl) 1 mg/Kg IM/IV/IO over 5 min max dose 50 mg
      • Epinephrine (1mg/1mL) 0.01 mg/Kg IM/IV/IO q3 min until stable or infusion started
          • Max 0.5 mg per dose (Intentionally larger than adult dosing)
          • Epinephrine infusion 0.01 mcg/Kg/min IV/IO, titrate to max 1 mcg/kg/min
      • Methylprednisolone (Solu-Medrol) 2 mg/Kg IV/IO max dose 125mg
      • Albuterol for 15 Kg or more, use adult dose
      • Albuterol for less than 15 Kg (1.25mg/ 3ml) nebulized with O2 at 6 lpm

    • Navigate

     

    References

    Campbell, Ronna. “Anaphylaxis: Emergency Treatment.” UpToDate, January 2022.
    Sicherer, Scott. “Prescribing Epinephrine for Anaphylaxis Self-Treatment.” UpToDate, January 2022.
    “U.S. Army Medevac Critical Care Flight Paramedic Standard Medical Operating Guidelines.” Jan. 2020.

     
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