Anaphylaxis Description
Anaphylaxis is a reaction that occurs in people who are severely allergic to certain foods or other substances. People with individual or family histories of hay fever, asthma, eczema, or food allergies are at increased risk of having an anaphylactic reaction at some point in their lives. People with asthma are particularly likely to have an anaphylactic reaction to food at some point. Anaphylaxis is an overreaction to an allergen caused by the body’s production of an antibody called immunoglobulin E or IgE. When a person who is susceptible to allergies first comes into con- tact with an allergen, the person’s immune system produces IgE antibodies that are specific to that allergen. The IgE antibodies then attach themselves to the surface of mast cells, which are specialized cells that lie within the connective tissue near the blood vessels. The next time the person encounters that specific allergen, the IgE antibodies trigger the release of a compound called histamine from the mast cells. The histamine in turn causes the tissue swelling, difficult breathing, and other symptoms of anaphylaxis.
Also Known As Immunologic reaction, anaphylactic shock
Cause Severe allergic reaction
Symptoms Difficulty breathing, nausea, vomiting, shock, loss of consciousness
Duration Starts a few minutes to a few hours after exposure ALAMY.

Some people have a recurrence of symptoms about six to eight hours after an episode of anaphylaxis. This recurrence is called a biphasic or delayed reaction.
Some substances are more likely to trigger anaphylactic reactions than others. The most common triggers are:
• Foods. Almost any food can cause anaphylaxis in persons who are sensitive to it; however, peanuts, nuts from trees (walnuts, cashews, and Brazil nuts), shellfish, fish, milk, and eggs are the most common offenders.
• Stinging insects. Yellow jackets, honeybees, paper wasps, hornets, and fire ants are the most likely to cause anaphylactic reactions.
• Medications. The drugs most likely to cause problems include penicillin and other antibiotics; antiseizure medicines; fluids given after surgery; antibodies made from horse serum; blood and blood products; radiocontrast dyes used in certain types of imaging studies; and morphine or similar pain medications.
• Latex. Latex is a natural material made from the rubber tree that is often used to make surgical gloves and other medical products. The greatest danger of anaphylaxis caused by latex occurs when the rubber material touches moist areas of the body or internal surfaces during surgery, because the allergen in latex can be absorbed by the body much more quickly.
• Exercise. Some people develop anaphylaxis when they exercise within a few hours of eating certain foods.
• Other causes. Although such cases are rare, semen, hormones, and extreme temper- atures have been reported to trigger anaphy- laxis in some people.