Anaphylaxis Management Guidelines
Diagnosis and Treatment
- The American Academy of Pediatrics recommends prompt epinephrine injection for sudden onset of any anaphylaxis symptoms after exposure to an allergen that previously caused anaphylaxis, and when uncertain whether symptoms represent anaphylaxis versus other conditions 1, 2
- Anaphylaxis is diagnosed when any one of three clinical criteria is met, and hypotension is not required for diagnosis, as stated by the American Academy of Pediatrics and the Journal of Allergy and Clinical Immunology 3, 4
- Delayed epinephrine administration is directly associated with increased hospitalization rates, hypoxic-ischemic encephalopathy, and death, according to the Pediatrics journal 3, 2
- The American Academy of Pediatrics and FDA-approved labeling specify epinephrine dosing as 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution) intramuscularly for adults and children ≥30 kg, and 0.01 mg/kg (up to 0.3 mg) intramuscularly for children <30 kg 3
Administration and Contraindications
- There are no absolute contraindications to epinephrine use in anaphylaxis, as stated by the Journal of Allergy and Clinical Immunology and the American Academy of Pediatrics 5, 6
- The American Academy of Pediatrics recommends intramuscular injection into the anterolateral thigh (vastus lateralis) for optimal absorption, as supported by the Radiology journal 6
- Even patients on beta-blockers should receive epinephrine, though they may require glucagon as adjunctive therapy if refractory, according to the Journal of Allergy and Clinical Immunology 5
Post-Administration Management
- All patients should be transferred to an emergency department for observation, even if symptoms resolve, as recommended by the Journal of Allergy and Clinical Immunology and the Radiology journal 4, 6
- Biphasic anaphylaxis occurs in 4-5% of cases, with higher risk in those requiring multiple epinephrine doses, and early epinephrine administration may reduce biphasic reaction risk, as found by the Journal of Allergy and Clinical Immunology and the Radiology journal 4, 6
Mechanism of Action of Epinephrine in Anaphylaxis
Beta-Adrenergic Effects
- The American Academy of Pediatrics recommends intramuscular injection of epinephrine into the lateral thigh, with a dose of 0.01 mg/kg for children, up to 0.3 mg, to alleviate bronchospasm, wheezing, and dyspnea 7
- The American Academy of Pediatrics suggests that epinephrine increases cardiac inotropy and chronotropy, supporting cardiovascular function, and inhibits further release of inflammatory mediators from mast cells and basophils, helping to halt the progression of the allergic reaction 8, 9
Pharmacokinetics
- Epinephrine has a relatively short duration of action, which may necessitate repeated dosing in prolonged anaphylactic reactions, according to the Journal of Allergy and Clinical Immunology 9
Clinical Application
- The American Academy of Pediatrics recommends that intramuscular injection into the lateral thigh is the preferred route for first-line treatment, with a dose of 0.3-0.5 mg of 1:1000 solution for adults 7, 10
- The Journal of Allergy and Clinical Immunology states that 10-20% of patients may require more than one dose for symptom resolution, and that repeated doses may be needed after 5-15 minutes if symptoms persist or worsen 9