Anaphylaxis Management

Introduction to Anaphylaxis

• Anaphylaxis is a severe, life-threatening systemic reaction resulting from sudden release of mediators from mast cells and basophils, characterized by acute onset with skin/mucosal involvement plus respiratory compromise or reduced blood pressure, with the more rapidly anaphylaxis develops, the more likely it is to be severe and potentially life-threatening 1

Diagnosis and Clinical Criteria

• Clinical criteria for diagnosis include acute onset with skin/mucosal involvement plus respiratory compromise or reduced blood pressure, and the rapid development of anaphylaxis is associated with a higher likelihood of severity and potential life-threatening outcomes 1

Patient Care and Management

• The American Academy of Allergy, Asthma, and Immunology recommends arranging follow-up with an allergist-immunologist as part of the management plan for patients with anaphylaxis 1
• Patients should be monitored for at least 4-6 hours after initial symptoms resolve, with longer observation recommended for severe initial reactions or patients requiring multiple doses of epinephrine, due to the risk of biphasic reactions 1
• Anaphylaxis should be recognized using validated clinical criteria, including acute onset of illness with involvement of skin/mucosal tissue plus respiratory compromise or reduced blood pressure, and treated promptly, as recommended by the American Academy of Pediatrics and the American Academy of Allergy, Asthma, and Immunology 2, 3, 4, 5

First-Line Treatment

• Epinephrine is the first-line treatment for anaphylaxis, with a recommended dose of 0.01 mg/kg of 1:1000 (1 mg/mL) solution, with a maximum of 0.3 mg in children and 0.5 mg in adults, as recommended by the Journal of Allergy and Clinical Immunology and the American Academy of Pediatrics 1, 5
• Epinephrine should be administered intramuscularly (IM) into the anterolateral thigh at a concentration of 1:1000 (1 mg/mL) solution, with a strength of evidence rated as high 2, 3
• Additional doses of epinephrine may be administered every 5-15 minutes if symptoms persist, as per the Journal of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma, and Immunology 1, 2, 3

Adjunctive Therapy

• Corticosteroids, such as prednisone 0.5-1 mg/kg orally or hydrocortisone 200 mg IV, should be administered after epinephrine, as recommended by the Journal of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma, and Immunology, with a strength of evidence rated as low 1, 2, 6
• Antihistamines such as promethazine or chlorphenamine (10 mg IV for adults) should be administered after hydrocortisone, but they are not effective for respiratory or cardiovascular manifestations and should not be relied upon to prevent biphasic anaphylaxis, with a strength of evidence rated as moderate 2, 6
• The American Academy of Allergy, Asthma, and Immunology recommends H1 antihistamine: Diphenhydramine 1-2 mg/kg (max 50 mg) every 6 hours for 2-3 days, alternative: Non-sedating second generation antihistamine, H2 antihistamine: Ranitidine twice daily for 2-3 days, and Corticosteroid: Prednisone daily for 2-3 days 7

Medication Administration

Patient Education and Follow-Up

• Patients should be prescribed an epinephrine autoinjector (2 devices) and provided with training on proper use, as recommended by the American Academy of Pediatrics 5
• A personalized anaphylaxis emergency action plan should be created, and follow-up with an allergist-immunologist should be arranged, according to the Journal of Allergy and Clinical Immunology and the American Academy of Pediatrics 1, 4, 5
• Patients should carry epinephrine auto-injectors at all times, as recommended by the American Academy of Pediatrics, with a strength of evidence rated as moderate 5

Special Considerations

• Infants <15 kg may require careful dosing of epinephrine, as the current lowest autoinjector dose (0.15 mg) may be high, according to the American Academy of Pediatrics 5
• For patients on beta-blockers, glucagon 1-5 mg IV over 5 minutes should be considered for refractory hypotension, as recommended by the Journal of Allergy and Clinical Immunology 1
• Continuous hemodynamic monitoring is essential when administering intravenous epinephrine, as recommended by the American Heart Association and the American Academy of Allergy, Asthma, and Immunology 8, 1