Anaphylaxis: severe episodes in hospital were rare

Clinical bottom line (level 4)

  1. Severe anaphylaxis was very rare in hospital, and few patients died of it.
  2. Common symptoms included respiratory, cardiovascular angioedema and pruritis.
The International Collaborative Study of Severe Anaphylaxis : Epidemiology 1998; 9: 141-146
Expires November 2004

The study

Prospective cohort study with unblinded, unobjective outcomes, not adjusted for confounding factors, not validated in an independent set of patients.

Setting: 9 acute hospitals, Europe and India

123 patients (aged median age ~53, 67% female) in hospital with severe anaphylaxis



Outcomes studied:
  • severe anaphylaxis
  • fatal anaphylaxis
  • respiratory symptoms
  • cardiovascular symptoms
  • angioedema or other swelling
  • pruritis

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)    		 NNF
    (95% CI)
    severe anaphylaxis ? 89/481752 0.018%
    (0.015% to 0.022%)    		 5400
    (4500 to 6800)
    fatal anaphylaxis ? 2/123 1.6%
    (0.0% to 3.9%)
    respiratory symptoms ? 97/123 79%
    (% to %)
    cardiovascular symptoms ? 86/123 70%
    (62% to 78%)
    angioedema or other swelling ? 60/123 49%
    (40% to 58%)
    pruritis ? 41/123 33%
    (25% to 42%)

    Comments

    1. Anaphylaxis may be IgE-mediated (anaphylactic) or triggered by non-IgE mechanisms (anaphylactoid); these subtypes are clinically indistinguishable.
    2. It is important to note this did not include community cases requiring hospitalisation, moderate or mild reactions of urticaria/angioedema, asthmatics, or intraoperative cases.

    Citation

    1. The International Collaborative Study of Severe Anaphylaxis , : An epidemiologic study of severe anaphylactic and anaphylactoid reactions among hospital patients: methods and overall risks. Epidemiology 1998; 9: 141-146
    Search Terms: ?
    Contributor: Mike Bennett and Chris Ball, November 1999
    Reviewer: David Lang

    Clinical Question.
    Patient suspected anaphylaxis
    Intervention or Exposure prevalence
    Outcome in-hospital, death