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Anaphylaxis and Food Allergy: Overview and Risk Factors  

Anaphylaxis is a rapid, life–threatening, systemic reaction. Although most frequently due to an IgE–mediated immediate–type hypersensitivity reaction, similar symptoms can occur as a result of an antibody–independent anaphylactoid mechanism. In anaphylaxis, activation of mast cells and/or basophils initiates a cascade that affects the respiratory, cardiovascular, integumentary, and gastrointestinal systems. Pathophysiologic processes include inflammation, vasodilation, bronchoconstriction/spasm with airway edema, and mucus secretion.

Common triggers in the hospital include drugs, blood products, and radiocontrast dyes. Outside the hospital, common triggers include venomous insect stings and certain foods, such as eggs, peanuts, dairy products, fish and shellfish, and tree nuts. Allergen–specific immunotherapy is a common cause of anaphylaxis as well.

Risk Factors

Age and gender. Allergy and anaphylaxis patterns vary by age and gender, due to stereotypical exposures. For example, adults have more reactions to venomous insects, such as bees, because they are more likely to have been previously exposed, compared with children. Likewise, females are more likely to be sensitized to neuromuscular blockers through a similar chemical in cosmetics.

Atopy. Individuals with a history of allergic diseases are said to be atopic and may have greater risk of severe or fatal reactions to anaphylaxis triggers.

Exposure history. Intravenous exposure tends to cause more severe reactions, because it circumvents epithelial or endothelial exposure barriers. Severity also increases with intermittent dosing (as compared with continuous dosing) or with greater intensity of exposure, as in seasonal or frequent occupational exposures.

History of anaphylaxis. Previous (especially recent) anaphylaxis is a risk factor for recurrence.


Anaphylaxis and Food Allergy: Diagnosis and Treatment >>