Anaphylaxis (Severe Allergic Reaction)

  • Medical Author:
    Allison Ramsey, MD

    Dr. Allison Ramsey earned her undergraduate degree at Colgate University and her medical degree at the University of Rochester School of Medicine and Dentistry. She completed her internal medicine training at the University of Rochester School of Medicine and Dentistry and remained at the university to complete her fellowship training in allergy and clinical immunology. Dr. Ramsey is board certified in internal medicine and allergy and immunology. Her professional interests include the treatment of drug allergy and eosinophilic disorders. She also enjoys teaching medical trainees. She is a member of the American Academy of Allergy, Asthma, and Immunology, the American College of Allergy, Asthma, and Immunology, the New York State Allergy Society, and the Finger Lakes Allergy Society. In her personal life, her interests include exercise, especially running and horseback riding; and spending time with her husband and two children.

  • Medical Author: Syed Shahzad Mustafa, MD
    Syed Shahzad Mustafa, MD

    After growing up in the Rochester area, Dr. Mustafa pursued his undergraduate studies at the Johns Hopkins University in Baltimore and attended medical school at SUNY Buffalo. He then completed his internal medicine training at the University of Colorado and stayed in Denver to complete his fellowship training in allergy and clinical immunology at the University of Colorado, National Jewish Health, and Children's Hospital of Denver.

  • Medical Editor: Melissa Conrad Stöppler, MD
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Quick GuideCould I Be Allergic? Discover Your Allergy Triggers

Could I Be Allergic? Discover Your Allergy Triggers

What are common causes of anaphylaxis?

The major causes of anaphylaxis include medications, foods, drugs, latex, and insect bites or stings (wasps, yellow jackets, hornets, honeybees, and fire ants), and latex. The causes of anaphylaxis are divided into two major groups:

IgE-mediated: This form requires an initial sensitizing exposure (an exposure to the substance that will later trigger the anaphylaxis) and then occurs on a subsequent exposure. It involves the coating of mast cells and basophils (cells in the blood and tissue that secrete mediators, the substances that cause allergic reactions) by an antibody called IgE, and the subsequent release of chemical mediators upon re-exposure. IgE-mediated anaphylaxis can occur with foods, drugs, latex, and insect stings. Although it may appear that IgE-mediated anaphylaxis occurs upon a first exposure to a food, drug, or insect sting, there must have been a prior sensitization from a previous exposure, which is often unknown. One may not remember an uneventful sting. The previous exposure to a food may not be recalled; it may occur in utero, through breast milk, or through the skin, particularly in individuals with eczema (atopic dermatitis).

Non-IgE-mediated: These reactions have the same symptoms as true anaphylaxis but do not require an IgE immune reaction. They are usually caused by the direct stimulation of the mast cells and basophils. In the past, they have been termed "anaphylactoid reactions." The same mediators are released as with IgE-mediated anaphylaxis, and the same effects are produced. This reaction can happen on initial, as well as subsequent, exposures, since no sensitization is required. This type of reaction usually occurs with medications. A common cause of a non-IgE-mediated reaction is IV contrast used in imaging studies.

Medically Reviewed by a Doctor on 7/21/2016

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