Management of Anaphylaxis
Immediately inject epinephrine 0.01 mg/kg intramuscularly (IM) in the mid-outer thigh (vastus lateralis muscle) as soon as anaphylaxis is recognized, with a maximum dose of 0.3 mg in prepubertal children and 0.5 mg in teenagers. 1
Immediate Recognition and Initial Actions
Anaphylaxis presents with sudden onset (minutes to hours) after trigger exposure and involves multiple organ systems 1:
- Skin/mucosal: itching, hives, swelling, flushing 1
- Respiratory: throat tightness, stridor, dyspnea, bronchospasm, wheeze, cyanosis 1
- Cardiovascular: tachycardia, hypotension, weak pulse, dizziness, collapse, shock 1
- Gastrointestinal: nausea, vomiting, crampy abdominal pain, diarrhea 1
- Neurologic: sense of doom, altered mental status, confusion 1
Critical first steps 1:
- Stop any medication infusion immediately if drug-related 1
- Maintain IV access 1
- Assess ABCs (Airway, Breathing, Circulation) and level of consciousness 1
- Call for emergency assistance (911/EMS in community, resuscitation team in hospital) 1
Patient Positioning
Position based on presenting symptoms 1:
- Hypotension: Trendelenburg position 1
- Respiratory distress: sitting upright 1
- Unconscious: recovery position 1
- Never allow standing, walking, or running 1
Epinephrine Administration
Primary treatment 1:
- Dose: 0.01 mg/kg IM (1 mg/mL dilution) 1
- Maximum: 0.3 mg prepubertal, 0.5 mg teenagers 1
- Site: mid-outer thigh (vastus lateralis) 1
- Repeat: second injection at 5-15 minutes if inadequate response 1
- Note: 6-19% of pediatric patients require a second dose 1
Additional Pharmacologic Management
H1/H2 Antagonists
- Diphenhydramine 50 mg IV plus ranitidine 50 mg IV 1
Corticosteroids
- Methylprednisolone 1-2 mg/kg IV every 6 hours (or equivalent) 1
- Prevents biphasic reactions but not critical for acute management 1
Cardiovascular Support for Refractory Hypotension
If epinephrine and fluids fail 1:
- Dopamine: 400 mg in 500 mL dextrose water at 2-20 mcg/kg/min, titrated to response 1
- Vasopressin: 25 units in 250 mL (0.1 U/mL), dose 0.01-0.04 U/min 1
- Norepinephrine: may be used if unresponsive to epinephrine 1
Special Circumstances
Bradycardia: atropine 600 mcg IV 1
Beta-blocker therapy: glucagon 1-5 mg IV infusion over 5 minutes for refractory cardiovascular effects 1
Oxygen: administer if needed 1
Post-Reaction Monitoring
- Monitor vital signs continuously until complete resolution 1
- 24-hour observation mandatory after severe reactions 1
- Transport to emergency department preferably by EMS, even if symptoms resolve 1
- Additional interventions may include supplemental oxygen, IV fluids, and other supportive measures 1
Common Pitfalls to Avoid
Delayed epinephrine administration is the most critical error—this is the leading cause of fatal anaphylaxis 1. Epinephrine must be given immediately upon recognition, not after trying antihistamines or corticosteroids first 1.
Incorrect positioning: allowing patients to stand or walk can precipitate cardiovascular collapse 1.
Premature discharge: patients require extended observation as biphasic reactions can occur hours after initial resolution 1.
Inadequate dosing: using autoinjectors (0.15 mg or 0.3 mg) may be suboptimal for some patients, particularly those at weight extremes 1.