From the Guidelines
Tryptase levels should not be routinely checked for patients with anaphylaxis in the Emergency Department (ED), as the diagnosis and management of anaphylaxis must occur rapidly and confirmatory testing has poor sensitivity. The clinical criteria proposed by the National Institute of Allergy and Infectious Diseases (NIAID) provide a helpful framework in approaching patients with acute allergic symptoms 1. While tryptase is a biomarker of mast cell activation, its measurement is not a prerequisite for the diagnosis of anaphylaxis, and treatment should never be delayed to obtain tryptase levels. Some key points to consider in the management of anaphylaxis include:
- The use of epinephrine administered intramuscularly as the first-line treatment for anaphylaxis 1
- The importance of prompt administration of epinephrine and other supportive measures in managing anaphylaxis
- The fact that normal tryptase levels do not exclude anaphylaxis, as some patients may have normal levels despite experiencing anaphylaxis
- The lack of clear evidence supporting the role of antihistamines and glucocorticoids in anaphylaxis, despite their routine use in anaphylaxis management 1. Given the acute and life-threatening nature of anaphylaxis, the priority should be prompt administration of epinephrine and other supportive measures, rather than delaying treatment to obtain tryptase levels 1.
From the Research
Anaphylaxis Diagnosis and Treatment
- Anaphylaxis is a life-threatening allergic reaction that requires prompt diagnosis and treatment in the Emergency Department (ED) 2, 3, 4, 5, 6
- The diagnosis of anaphylaxis is clinical, but plasma tryptase and urinary histamine levels can be elevated, allowing for diagnostic confirmation 6
- Current guidelines recommend quick diagnosis using standard criteria, first-line treatment with epinephrine, and discharge with a prescription for an epinephrine auto-injector and a referral for follow-up 3, 4, 5
Tryptase Levels in Anaphylaxis
- Plasma tryptase levels can be elevated in anaphylaxis, allowing for diagnostic confirmation 6
- However, diagnostic testing, including tryptase levels, should not delay treatment as results may not be immediately available 6
- There is no clear recommendation on whether tryptase levels should be checked for patients with anaphylaxis in the ED, but it can be used as a diagnostic tool to confirm anaphylaxis 6
Emergency Department Management
- Treatment of anaphylaxis in the ED should include a combination of intramuscular epinephrine, supplemental oxygen, and intravenous fluids 2, 3, 5
- Avoiding treatment delays is crucial, as symptoms can progress rapidly 2, 5
- Patients with anaphylaxis should be given a prescription for at least 2 epinephrine autoinjectors, an initial emergency action plan, education about avoidance of triggers, and a referral to an allergist upon discharge from the ED 3, 4, 5