Predictors of severe systemic anaphylactic reactions in patients with Hymenoptera venom allergy: importance of baseline serum tryptase-a study of the European Academy of Allergology and Clinical Immunology Interest Group on Insect Venom Hypersensitivity

J Allergy Clin Immunol. 2009 Nov;124(5):1047-54. doi: 10.1016/j.jaci.2009.08.027.


Background: Severe anaphylaxis to honeybee or vespid stings is associated with a variety of risk factors, which are poorly defined.

Objective: Our aim was to evaluate the association of baseline serum tryptase concentrations and other variables routinely recorded during patient evaluation with the frequency of past severe anaphylaxis after a field sting.

Methods: In this observational multicenter study, we enrolled 962 patients with established bee or vespid venom allergy who had a systemic reaction after a field sting. Data were collected on tryptase concentration, age, sex, culprit insect, cardiovascular medication, and the number of preceding minor systemic reactions before the index field sting. A severe reaction was defined as anaphylactic shock, loss of consciousness, or cardiopulmonary arrest. The index sting was defined as the hitherto first, most severe systemic field-sting reaction. Relative rates were calculated with generalized additive models.

Results: Two hundred six (21.4%) patients had a severe anaphylactic reaction after a field sting. The frequency of this event increased significantly with higher tryptase concentrations (nonlinear association). Other factors significantly associated with severe reactions after a field sting were vespid venom allergy, older age, male sex, angiotensin-converting enzyme inhibitor medication, and 1 or more preceding field stings with a less severe systemic reaction.

Conclusion: In patients with honeybee or vespid venom allergy, baseline serum tryptase concentrations are associated with the risk for severe anaphylactic reactions. Preventive measures should include substitution of angiotensin-converting enzyme inhibitors.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anaphylaxis / blood
  • Anaphylaxis / enzymology
  • Anaphylaxis / epidemiology*
  • Animals
  • Bee Venoms / immunology*
  • Cohort Studies
  • Female
  • Humans
  • Hypersensitivity / immunology*
  • Insect Bites and Stings / immunology*
  • Male
  • Middle Aged
  • Prognosis
  • Prospective Studies
  • Retrospective Studies
  • Tryptases / blood*
  • Wasps / immunology*


  • Bee Venoms
  • Tryptases