Clinical features and severity grading of anaphylaxis

Area of Science:

• Allergy and Immunology
• Emergency Medicine
• Clinical Toxicology

Background:

• Existing grading systems for acute systemic hypersensitivity reactions are inconsistent and lack a clear definition of anaphylaxis.
• Current systems present deficiencies in accurately classifying reaction severity.

Purpose of the Study:

• To develop a straightforward grading system and definition for anaphylaxis.
• To identify predictors associated with the severity of hypersensitivity reactions.

Main Methods:

• Retrospective analysis of 1149 systemic hypersensitivity reaction case records from emergency departments.
• Logistic regression used to correlate reaction features with hypotension and hypoxia for grading system construction.
• Assessment of epinephrine use, etiology, age, sex, comorbidities, and medications for association with reaction grade.

Main Results:

• Severe reactions defined by confusion, collapse, unconsciousness, and incontinence (associated with hypotension/hypoxia).
• Moderate reactions characterized by diaphoresis, vomiting, dyspnea, wheeze, chest/throat tightness, nausea, and abdominal pain.
• Mild reactions limited to skin manifestations (urticaria, erythema, angioedema); grades correlated with epinephrine use.
• Older age, insect venom, and iatrogenic causes identified as independent predictors of severity.
• Preexisting lung disease linked to increased hypoxia risk.

Conclusions:

• The proposed grading system offers potential value for defining anaphylaxis severity in clinical practice and research.
• The moderate and severe grades establish a functional definition of anaphylaxis.
• Age, reaction trigger, and pre-existing lung disease are significant determinants of anaphylaxis severity.