Kristina Wilson, MD, MPH, FAAP, CAQSM


  • The causative agent in anaphylaxis remains unknown in up to 1/3 of cases.

  • Food is the most common causative agent (about 1/3 of known cases) in children.

  • Pharmacotherapeutic agents are the most common cause in adults.

  • Other common causes include Hymenoptera stings and latex.

  • Key to management and treatment is early recognition and immediate initiation of appropriate medical therapy.

  • Epinephrine is the undisputed initial therapy for anaphylaxis, and its administration should never be delayed.

  • Failure to inject epinephrine promptly has been identified as the most important factor contributing to death in patients experiencing anaphylaxis.


  • Severe, potentially life-threatening systemic hypersensitivity reaction

  • Allergic type mediated by immunoglobulin E (IgE):

    • Involves the respiratory and/or cardiovascular systems

    • Patients may have a history of less severe reaction previously on exposure to relevant allergen.

  • Exercise-induced anaphylaxis (EIAn):

    • Occurs in response to physical exertion

    • Subset of patients must have associated food trigger—food-dependent exercise-induced anaphylaxis (FDEIAn).

  • Cold urticaria:

    • Reproducible, rapid onset of erythema, pruritus, and edema after exposure to cold

    • Most idiopathic

    • Occasionally involves abnormal circulating proteins (i.e., cryoglobulins or cryofibrinogens); agglutinates or precipitates at lower temperatures


Death rates from the most common causes of anaphylaxis have varied:

  • Food induced has increased.

  • Insect sting has declined.

  • Drug induced has increased.


  • 8 to 50/100,000 person-years in Western countries

  • Incidence rates vary widely owing to differences in sample populations, data-collection methods, and varying definitions of anaphylaxis.


Lifetime prevalence of 0.05-2.0% in Western countries (1), rising especially in children


  • Allergic: IgE-mediated:

    • Drugs

    • Venom

    • Latex

    • Vaccines

    • Food

  • Nonallergic: direct basophil/mast cell-mediated:

    • Radiocontrast dye

    • Opioid drugs


  • Prior anaphylaxis event can predict subsequent anaphylaxis:

    • As the only risk factor, prior anaphylaxis has a poor ability to identify patients who might develop anaphylaxis.

    • 14% of anaphylaxis admissions for peanut sensitivity have a prior history of anaphylaxis.

  • Often occurs following a previous mild allergic reaction to the same allergen

  • Most proposed risk factors have limited value owing to a low specificity:

    • Coexisting atopic disease; especially poorly controlled asthma

    • Older age at first reaction to food allergy

  • Clinical risk factors for fatality in anaphylactic reactions (2):

    • Severe or uncontrolled asthma

    • Cardiovascular disease

    • Mastocytosis

Mar 14, 2020 | Posted by in SPORT MEDICINE | Comments Off on Anaphylaxis
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