Causes and Symptoms (Magill’s Medical Guide, Sixth Edition)
Allergic reactions occur when the immune system is stimulated to protect the body from foreign organisms known as allergens. Allergens, usually proteins, are perceived by the body as potentially harmful. When the immune system is activated, two types of white blood cells respond: phagocytes and lymphocytes. Phagocytes destroy bacteria, viruses, and parasites. Lymphocytes destroy other types of harmful organisms, and it is these white blood cells that respond when a food is perceived as harmful. Therefore, when an allergen is encountered, white blood cells respond and attach an immunoglobulin (Ig) antibody to it. Five different immunoglobulin antibodies can be activated, and each has a different responsibility. Immunoglobulin E (IgE) is the antibody that responds during a food allergy reaction. Marking an allergen with an Ig antibody distinguishes it from healthy tissue and cells. This in turn allows white blood cells to release a chemical spray, usually histamine, which targets and destroys only the harmful allergen.
Food is essential for life and good health, and the exact reason why a food substance is identified as harmful is still inconclusive. Genetics provide the strongest link to food allergy incidence. Research studies show that a family history of allergies increases the chance of developing all allergies, including those to food. If both parents have an allergy, there is a 70 to 80 percent chance that their...
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Treatment and Therapy (Magill’s Medical Guide, Sixth Edition)
Allergic reactions to foods must always be taken seriously since symptoms can escalate from minor to life-threatening in a matter of minutes. Individuals with asthma are at the highest risk for severe food reactions. When a severe food reaction occurs, an injection of epinephrine and emergency medical treatment must be administered as quickly as possible. Mild reactions may require an oral/intravenous antihistamine or steroid medication or topical hydrocortisone ointment. Even when symptoms seem to be over or under control, the individual must still be continually monitored for four to six hours after the initial reaction because symptoms can progress rapidly to life-threatening as a result of a delayed reaction known as a biphasic reaction.
The only way to prevent a food allergy reaction is by strictly avoiding the food. Allergic individuals must be careful at all times about every food that they eat because food allergens can go airborne or be used in the processing or cooking of a food. Reading food ingredient labels (disclosures by food processing manufacturers are required by law) and questioning food preparers about prepared foods are critical prevention steps that anyone living with a food allergy must take. However, accidental exposures can still occur no matter how careful an individual is. Therefore, it is essential that an Epi-Pen or similar device and a food allergy action plan be carried at all times....
(The entire section is 399 words.)
Perspective and Prospects (Magill’s Medical Guide, Sixth Edition)
It has long been recognized that surviving an illness often provides protection against that illness in the future. This connection between immunity and disease was particularly apparent during the ancient plagues of smallpox. Smallpox, an infectious virus, is estimated to have killed three hundred to five hundred million people worldwide in just the twentieth century. Ancient Egyptian mummies show the ravages of this disease and Greek historians record the decimated population during the Athenian plague (430-426 b.c.e.). Historians record efforts to increase population survival rates by inhaling crushed smallpox scabs (early immunization technique) and inoculations using pus from smallpox lesions (early vaccination technique) to prevent the disease.
During the eighteenth and nineteenth centuries many lifesaving advances were made in the fields of science and medicine. The body’s defense mechanisms, known as immunology, were explored and many diseases successfully eradicated over time. Preventive vaccines to protect and increase life span were developed and are now accepted medical practice. However, understanding the mechanism of food allergies has taken much longer. Carl Prausnitz-Giles, a bacteriologist-immunologist, was the first to discover that food allergies were intimately tied to the immune system. Scientists Kimishige Ishizaka and Terako Ishizaka discovered that IgE was the principal agent for food...
(The entire section is 373 words.)
For Further Information: (Magill’s Medical Guide, Sixth Edition)
Melina, Vesanto, Jo Stepaniak, and Dina Aronson. Food Allergy Survival Guide. Summertown, Tenn.: Healthy Living, 2004. Written by dietitians, a practical resource exploring how to live with food allergies. Recipes are included.
Richer, Alice C. Food Allergies. Westport, Conn.: Greenwood Press, 2009. Written by a registered dietitian, this book is a comprehensive resource that helps readers learn the causes of adverse food reactions, distinguish between true food allergies and food hypersensitivities, and outlines management strategies.
Sicherer, Scott H. Understanding and Managing Your Child’s Food Allergies. Baltimore: Johns Hopkins University Press, 2006. Comprehensive resource exploring every aspect of food allergies in children. Written by a prominent physician and researcher in the field.
Wood, Robert A. Food Allergies for Dummies. Hoboken, N.J.: Wiley, 2007. Written by an allergist specializing in food allergies, an easy-to-understand and basic resource explaining what food allergies are, how they are diagnosed, and strategies to live with them.
(The entire section is 148 words.)