Definition :
Food allergies are the body’s response to proteins found in food. For more than 12 million Americans alone, food allergy is a significant medical condition. All food contains proteins that enter the body when the food is eaten, or in some cases if it is touched. Allergic reaction occurs when the body reacts to these proteins as if they were harmful, and for individuals with food allergy, the offending food is harmful.
Symptoms of food allergy vary and can range from mildly annoying to dangerous and life threatening. Symptoms of food allergy include:
- tingling of the mouth
- tingling or numbness in arms or legs
- rash or hives
- itching
- abdominal cramps
- vomiting
- diarrhea
- breathing difficulties
- sudden drop in blood pressure (hypotension)
- swelling of the tongue
- swelling of the throat
- loss of consciousness
- death
The most serious symptom of food allergy is anaphylaxis. Anaphylaxis, also called anaphylactic shock, is a sudden and potentially life threatening allergic reaction in which the whole body reacts to an allergen. During anaphylaxis the airway constricts making breathing difficult. Vomiting and diarrhea may also occur as the digestive tract constricts. The skin may swell and become itchy with rash or hives especially in the face. This swelling may block airways as well. The heart may race and the heart beat may become irregular as blood vessels around the heart expand.
Anaphylaxis is caused when the body encounters a substance it believes is toxic. This substance is an allergen and is also called IgE. When this occurs, the body produces a substance called histamine. Histamine is a protein that the body releases in reaction to a substance in the blood that the body believes is toxic. Histamine causes blood vessels to dilate or become larger and this causes the symptoms of anaphylaxis. The treatment for anaphylaxis is medication called antihistamine. The most common antihistamine is diphenhydramine hydrochloride which is found over–the–counter drugs such as Benadryl. If taken immediately, this antihistamine can stop anaphylaxis before it becomes too serious.
In cases of severe allergy, an injection of a strong antihistamine called epinephrine or adrenaline may be needed. If allergy is suspected or if an individual has had a previous allergic reaction, an injectable form of epinephrine may be prescribed. An auto–injectable form of epinephrine that looks similar to a large ball point pen is kept on hand at all times. If a severe allergic reaction occurs, the auto–injector (brand named Epi-Pen) is held against the skin and the medication is administered with a shot. Epinephrine is a strong antihistamine that stops anaphylaxis very quickly.
There is no cure for food allergies; however, food allergies may be prevented. By avoiding foods that cause allergic reactions, an individual can prevent allergic reaction. Avoiding foods that cause allergic reactions is called an elimination diet.
Before food allergies can be avoided, the offending food must be identified. There are eight foods that cause 90% of all food allergies these foods include:
- milk
- eggs
- peanuts
- tree nuts (walnuts, cashews, pecans, etc.)
- fish
- shellfish
- soy
- wheat
Origins :
The fact that some foods cause physical illness has been recognized throughout history. It was the ancient Greek, Lucretius who first said, ‘‘One man’s food may be another man’s poison.’’ Throughout history, people have avoided foods that seemed to cause ill health. In the 1960s researchers began to document food allergies and to verify that avoiding these foods reduced or eliminated the allergy symptoms all together.
In the following 50 years, screening tests such as blood tests and skin tests were developed to assist in identifying food allergies. Treatment including antihistamines and anti–inflammatory medications have helped relieve symptoms, but an elimination diet remains the single most effective method to treat food allergies.
Description :
Food allergies occur when the body has an abnormal reaction to a food eaten or touched. In some individuals, certain foods cause the body to produce histamine. This histamine travels throughout the body causing symptoms such as hives, swelling, wheezing, vomiting, or diarrhea. Once a food allergy has been identified, an elimination diet is the only effective treatment. By eliminating the food that causes the allergic reaction, allergic reaction to food may be prevented.
To identify food allergies, a doctor first records a detailed medical history. The patient will usually keep
a food diary documenting exactly what is eaten and when. The patient will also record any physical symptoms and when they occur. In most cases, patterns of reaction to specific foods can be seen in the food diary. Other means of diagnosis food allergies includes
Blood tests (RAST, CAP–RAST)—A sample of
blood is drawn and sent to the lab. These tests measure antibodies in the blood. These antibodies form in response to specific foods. These antibodies occur after the body has been exposed to a food and has
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