V1.2.4. March 27, 2023

Definition
“Anaphylaxis is a severe, systemic hypersensitivity reaction that is rapid in onset and characterized by life-threatening airway, breathing, and/or circulatory problems, and that is usually associated with skin and mucosal changes” (3).

Clinical criteria for the diagnosis of anaphylaxis. Anaphylaxis is likely when 1 of 3 criteria are fulfilled: (1) acute onset of an illness (minutes to hours) with involvement of the skin, mucosal tissue, or both with either respiratory involvement or reduced blood pressure (BP)/associated symptom of end-organ dysfunction; or (2) ≥2 of the following that occur rapidly after exposure to a likely allergen for the patient, including (i) involvement of skin-mucosal tissue, (ii) respiratory involvement, (iii) reduced blood pressure or associated symptoms, or (iv) gastrointestinal symptoms; or (3) reduced blood pressure as a result of exposure to a known allergen trigger. 

Proposed diagnostic criteria by the National Institute of Allergy and Infectious Diseases/Food Allergy and Anaphylaxis Network (NIAID/ FAAN)(2), are proposed to be useful to the emergency department:

• Sensitivity 96.7%

• Specificity 82.4%

• Severe anaphylaxis and/or the need for >1 dose of epinephrine to treat anaphylaxis are risk factors for biphasic anaphylaxis. Additional risk factors include wide pulse pressure, unknown anaphylaxis trigger, cutaneous signs and symptoms, and drug trigger in children.

• Extended observation is suggested for patients with resolved severe anaphylaxis and/or those with need for >1 dose of epinephrine.

• Antihistamines and/or glucocorticoids are not reliable interventions to prevent biphasic anaphylaxis but may be considered as secondary treatment.

• Evidence supports a role for antihistamine and/or glucocorticoid premedication in specific chemotherapy protocols and rush aeroallergen immunotherapy.

• Evidence is lacking to support the routine use of antihistamines and/or glucocorticoid premedication in patients receiving low- or iso-osmolar contrast material to prevent recurrent RCM anaphylaxis.

• Administer epinephrine as the first-line pharmacotherapy for uniphasic and/or biphasic anaphylaxis.

• Do not delay the administration of epinephrine for anaphylaxis.

• After diagnosis and treatment of anaphylaxis, all patients should be kept under observation until symptoms have fully resolved.

• All patients with anaphylaxis should receive education about anaphylaxis, risk of recurrence, trigger avoidance, self-injectable epinephrine, and thresholds for further care, and they should be referred to an allergist for follow-up evaluation.

• Epinephrine

• Antihistamines

• Famotidine

• Chlorpheniramine

• Cetirizine

• Ranitidine

• Hydrocortisone

• Betamethasone

• Dexamethasone

• Methylprednisolone

• Glucagon

• Albuterol

1. Campbell RL, Hagan JB, Manivannan V, et al. Evaluation of national institute of allergy and infectious diseases/food allergy and anaphylaxis network criteria for the diagnosis of anaphylaxis in emergency department patients. J Allergy Clin Immunol. 2012;129(3):748-752. doi:10.1016/j.jaci.2011.09.030
   Journal of Allergy and Clinical Immunology (Open Access)

2. Campbell RL, Li JT, Nicklas RA, Sadosty AT; Members of the Joint Task Force; Practice Parameter Workgroup. Emergency department diagnosis and treatment of anaphylaxis: a practice parameter. Ann Allergy Asthma Immunol. 2014;113(6):599-608. doi:10.1016/j.anai.2014.10.007
   Annals of Allergy and Immunology (Open Access)

3. Reber LL, Hernandez JD, Galli SJ. The pathophysiology of anaphylaxis. J Allergy Clin Immunol. 2017;140(2):335-348. doi:10.1016/j.jaci.2017.06.003
   JACI (Open Access)

4. Shaker MS, Wallace DV, Golden DBK, et al. Anaphylaxis-a 2020 practice parameter update, systematic review, and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) analysis. J Allergy Clin Immunol. 2020;145(4):1082-1123. doi:10.1016/j.jaci.2020.01.017
   Journal of Allergy and Clinical Immunology (Open Access)