Summary of Brighton Criteria Case Definitions for Anaphylaxis17

For all levels of diagnostic certainty: anaphylaxis is a clinical syndrome characterized by sudden onset, rapid progression of signs and symptoms, AND involving multiple (≥2) organ systems, as follows:
Level 1 of diagnostic certainty
 • ≥1 major dermatological AND
 • ≥1 major cardiovascular AND/OR ≥1 major respiratory criterion
Level 2 of diagnostic certainty
 • ≥1 major cardiovascular AND ≥1 major respiratory criterion
 • ≥1 major cardiovascular OR respiratory criterion AND
  1. ≥1 minor criterion involving ≥1 different system (other than cardiovascular or respiratory systems)
  2. (≥1 major dermatologic) AND (≥1 minor cardiovascular AND/OR minor respiratory criterion)
Level 3 of diagnostic certainty
 • ≥1 minor cardiovascular OR respiratory criterion
 • ≥1 minor criterion from each of ≥2 different systems/categories
  • The case definition should be applied when there is no clear alternative diagnosis for the reported event to account for the combination of symptoms.