Allergic Reaction To Oysters

Once known as as a poor man's food, oysters now appear as high-priced menu items at seafood restaurants. Oyster bars, oysters Rockefeller and the oyster po' boy present the shellfish in raw or cooked variations. All oyster-based delicacies, however, are permanently off-limits to the millions who experience an allergic reaction to them. Unlike many other food allergies, oyster allergy is a lifetime condition.

Shellfish Allergies

About 7 million people in the U.S., or more than 2 percent of the population, have allergic responses to shellfish, according to the American College of Allergy, Asthma and Immunology. This frequency places shellfish among eight foods most commonly associated with food allergies. Most of people allergic to oysters develop their sensitivity as adults, notes the ACAAI. Persons allergic to oysters sometimes, but not always, experience reactions to crab, lobster, shrimp and other shellfish.

Cause

An allergic reaction to oysters, or any food, results when the body's immune system mistakenly identifies a compound -- usually protein -- in the food as a hostile invading organism. The immune system defends against the oysters by releasing an immunoglobulin E, or IgE, antibody that specifically targets oyster protein. The IgE stimulates certain blood or tissue cells to release histamines, the actual chemicals responsible for allergy symptoms.

Oyster Allergy Symptoms

Oyster allergy symptoms surface within minutes to a few hours after exposure. They affect people who handle or consume oysters. Early signs of a reaction typically appear on the skin. Symptoms include swelling itching in the mouth area, bloating of the face, hands or lips, inflamed, itching skin or hives. Oysters entering the digestive tract produce abdominal distress, with nausea, vomiting, diarrhea or cramping. Respiratory reactions include labored breathing, wheezing or asthma. Respiratory reactions can occur simply from breathing airborne proteins from cooked oysters.

Anaphylaxis

Anaphylaxis, a severe allergic reaction, affects sensitive people within minutes of their exposure to oysters. Untreated anaphylaxis can be fatal in as little as 15 minutes, according to a May 2010 article "The New York Times." People in anaphylactic shock experience a racing heartbeat, chest or throat tightening with severe respiratory distress, cold, clammy skin, and dizziness. They often lose consciousness. Anaphylaxis requires immediate medical attention.

Living with Oyster Allergy

While packaged foods in the United States must list lobster, crab or other crustaceans on their labels, the same isn't true of oysters. Any shellfish processed with oysters are potentially allergenic. Dining at restaurants where oysters are on the menu can mean exposure to foods cross-contaminated with oyster protein during handling, or inhaling oyster proteins from cooking vapors. The only way to avoid an allergic reaction from oysters is to avoid any place where exposure oysters or oyster proteins might occur.