Causes of Food Allergy

Topics: Allergy, Immune system, Asthma Pages: 5 (1731 words) Published: November 28, 2010
What Causes Food Allergy?
Food allergies occur when the immune system mounts an attack on certain proteins in certain foods. The substances in the food that cause this immune system response are called allergens. The immune system is a complex network of cells and molecules that help defend the body against unknown substances. When a properly functioning immune system detects an unknown substance, it responds to this threat by producing proteins called antibodies against the invaders. The antibodies will recognize and attack this foreign substance when they next encounter it. This "battle" is what causes the allergy symptoms. In food allergy the immune system mistakenly sees a harmless substance in the food as harmful, and churns out antibodies known as immunoglobulin to attack it. These antibodies will circulate in the blood, attached to special cells called mast cells, which are part of the immune system. This occurs in order to protect against future invasion by that substance. The next time a person eats that food, the substance to which he is allergic the allergen enters the body, and attaches to the immunoglobulin on mast cells. The mast cells respond by releasing a host of powerful chemicals, including histamine, to protect the body. This produces allergic symptoms. Histamine contributes to inflammation and causes symptoms such as swelling on the skin and itching. It is responsible for the hives, or welts, that appear on the skin when a doctor tests for allergy. These hives show the presence of immunoglobulin and are one of the best indications of allergy. What are the Symptoms of Food Allergy?

In an allergy attack, the symptoms experienced depend on where in the body histamine is released. Allergic reactions to foods most often involve the skin, the stomach and intestines, and the mouth and the respiratory system. A life threatening reaction may involve all parts of the body including the cardiovascular system so that the individual goes into shock this will lead to blood pressure to fall dangerously low. A severe reaction could start very suddenly and involve only a fall in blood pressure or shock. It is important to know that a life threatening reaction may occur with no skin symptoms. Symptoms may appear within minutes or as long as several hours after eating the allergy provoking food. An allergy reaction in the skin may cause hives, itchy, scaly rash called eczema, redness or flushing, and swelling. In the digestive system an allergy reaction may cause stomach pain, nausea, vomiting, and diarrhea. An the common respiratory symptoms from an allergic reaction may include sneezing, coughing, runny nose, wheezing, closing of the throat and breathing difficulties, as part of a severe allergic reaction known as anaphylaxis and, itchy, watery eyes are often included with respiratory symptoms. Life-Threatening Reactions (Anaphylaxis)

The most severe allergic reaction is anaphylaxis, or anaphylactic shock, a severe reaction that involves most of the body. Anaphylaxis can affect several parts of the body at the same time, including the skin and the digestive and respiratory systems or it might just involve respiratory or cardiovascular symptoms. In addition to producing the symptoms of food allergy, it may also lead to difficulty in breathing, falling blood pressure and unconsciousness. Although very rare, anaphylaxis can be fatal. Each year, about 150 people in the United States die of food-related anaphylaxis. Which Foods Cause Allergic Reactions?

Virtually any food can trigger an allergic response. However, studies have found that 80 to 90 percent of children with food allergies are allergic to one or more of these foods for example eggs, peanuts, milk, wheat, and soy. Other common triggers include tree nuts such as almonds, pecans, cashews, Brazil nuts and walnuts, and fish and shellfish for example, crab and shrimp. Various other foods and certain food additives and spices may cause allergic reactions. Cross...
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