is an ,'' to which they have already become sensitized. Minute amounts of allergens may cause a life-threatening anaphylactic reaction. Anaphylaxis may occur after ingestion, skin contact, injection of an allergen or, in rare cases, inhalation."Anaphylaxis." Health. 17 January 2002 . AllRefer.com . 29 Jan 2007
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, the most severe type of anaphylaxis, occurs when an allergic response triggers a quick release from Mast Cell s of large quantities of Immunological mediators ( Histamine s, Prostaglandin s, Leukotriene s) leading to systemic Vasodilation (associated with a sudden drop in blood pressure) and Edema of Bronchial Mucosa (resulting in Bronchoconstriction and difficulty breathing). Anaphylactic shock can lead to death in a matter of minutes if left untreated.
An estimated 1.24% to 16.8% of the population of the United States is considered "at risk" for having an anaphylactic reaction if they are exposed to one or more allergens, especially penicillin and insect stings. Most of these people successfully avoid their allergens and will never experience anaphylaxis. Of those people who actually experience anaphylaxis, up to 1% may die as a result.Neugut, Alfred, Anita Ghatak and Rachel Miller. "Anaphylaxis in the United States: An Investigation Into Its Epidemiology." Arch Intern Med. 161.108 January 2001 15-21. 29 January 2007 . Anaphylaxis results in fewer than 1,000 deaths per year in the U.S. (compared to 2.4 million deaths from all causes each year in the U.S. {Link without Title} ). The most common presentation includes sudden cardiovascular collapse (88% of reported cases of severe anaphylaxis).
Researchers typically distinguish between "" and "'''pseudo-anaphylaxis'''." The symptoms, treatment, and risk of death are identical, but "true" anaphylaxis is always caused directly by Degranulation of Mast Cell s or basophils that is mediated by Immunoglobulin E (IgE), and pseudo-anaphylaxis occurs due to all other causes. The distinction is only important for researchers who are studying mechanisms of allergic reactions. Due to the word "pseudo", it may frustrate patients who feel they are being told that a life-threatening allergic reaction isn't "real".
Symptoms of anaphylaxis are related to the action of ( IgE ) and other Anaphylatoxin s, which act to release Histamine and other mediator substances from Mast Cell s (degranulation). In addition to other effects, histamine induces Vasodilation of Arterioles and constriction of Bronchioles in the lungs, also known as Bronchospasm (constriction of the airways).
Symptoms can include the following:
