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Hitachi Chemical Diagnostics, Inc. Hitachi Chemical Diagnostics, Inc.

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Who gets Allergies?

Over the past decade, allergies have increased dramatically in western culture. Twenty to 40 percent of the population suffers from allergy and it is generally noted that at least one out of every four children suffers from allergies. In fact, even if only one parent has allergies, about 25 percent of the time a child will too, and if both parents have allergies, there is more than a 50 percent chance of having an allergic child.

People who suffer from allergies are often sensitive to more than one allergen. Symptoms may not appear until they are exposed to an intolerable amount of a single allergen or smaller amounts of multiple allergens. This makes it important to identify the specific allergens responsible. With this information, a plan for prevention or treatment can make the difference between a chronic illness and a productive, healthy lifestyle.

What is an Allergy?

An allergy is an overreaction of the body's immune system to an ordinarily harmless substance. Allergies are not just seasonal. They exist throughout the year, indoors and out, and affect people of all ages. Allergies can impair performance, interfering with sleep, cognitive skills and even physical ability. Occasionally, allergies can cause anaphylaxis, a potentially life threatening reaction. Many things in our every day lives can trigger an allergic reaction, including animal dander, house dust mites, foods, grasses, trees, weeds, and molds.

Animal Dander

Traditionally, fur is believed to cause allergic reaction to animals, but researchers have found the cause to be proteins secreted by oil glands in the animal's skin. Dander, saliva, and urine, which carry these proteins, eventually dry up and release the proteins into the air.

Foods

In a typical food allergy, the immune system produces antibodies to a specific food. Commonly troublesome food allergens include milk, eggs, peanut and shellfish.

Grasses, Trees and Weeds

Tiny particles of pollen are released into the air during certain seasons where they can enter human noses and throats, triggering an allergic reaction. Patients suffering from seasonal "hay fever" may also have sensitivities to perennial allergens such as house dust. Sensitivities to such perennial allergens may contribute to the severity of seasonal symptoms.

House Dust Mites

This allergic reaction results from the airborne waste product of Dust Mites, tiny organisms that live in the dust of areas inhabited by people like bedding, upholstered furniture, drapes, and carpets.

Molds

Much like pollens, molds release spores into the air where they can enter human noses and throats, triggering an allergic reaction. Mold allergies can be perennial or seasonal depending on the geographic area and are most noticeable indoors in damp environments, while others are a problem outdoors on windy days.

Diagnosing Allergies

A physician’s first step is to identify allergic patients. Individual patients are screened to (1) identify the allergen; (2) establish a causal relationship between exposure and the occurrence of symptoms; and (3) identify the immunological mechanism involved. To establish the immunologic mechanism, allergen-specific antibodies called IgE must be identified and measured. This is done by skin prick testing or in vitro allergy testing.

Skin Prick Testing

An allergy specialist usually performs skin testing after a referral from a General Practitioner. There are no age limits for skin testing. Results are usually available within 20 minutes. Commonly performed on the forearm and sometimes the back, the skin is cleaned with alcohol and an allergen extract is pricked into the skin. If an allergy is present, a small itchy bump and surrounding redness often referred to as a "wheal and flare" will appear in approximately 15 minutes. This indicates the presence of IgE antibodies capable of recognizing the shape of that specific allergen, like a lock "recognizes" a key. There are some side effects of skin testing. Medications with anti-histamine-like actions must usually be avoided for three to thirty or more days before testing so as not to interfere with test results. After testing, swelling and itching typically resolve within an hour however for some patients this may persist longer.

In Vitro Testing

In Vitro Testing… Performed in vitro, or 'outside the body,' this laboratory blood test can measure specific IgE levels in patient serum. Medications need not be discontinued, as they do not interfere with the reliability and performance of the test. The doctor simply draws a small amount of blood during an office visit, has it tested in a lab and usually has the results within 24 hours. The CLA® Allergy Test and the OPTIGEN Allergy Test offer reliable results in agreement with skin tests. In fact, many professional medical societies recommend the use of in vitro tests like the CLA and OPTIGEN Allergy Tests to confirm the diagnosis of allergy in symptomatic patients.

Treatment Options

Once an allergy diagnosis is made, a specific treatment program can begin. Allergy management falls into three main categories: avoidance, medication and immunotherapy.

Avoidance

Once the source of an allergy is identified, one solution may be to simply remove or control it. This approach is most effective with food and animal allergies. In addition to standard heating and cooling air filters, portable devices can be especially helpful in reducing animal allergens in individual rooms. As for outdoor airborne allergens such as pollens and mold spores, it is obviously difficult to effectively diminish an individual's exposure especially during the seasons in which they are abundant. Allergy avoidance literature is readily available and can serve as a useful tool in coping with allergy and asthma symptoms.

Pharmacotherapy (Medication)

Effective new prescription drugs can reduce allergy symptoms. Many are often effective immediately, producing benefits by neutralizing the effects of the chemicals released in the body during an allergic reaction. Medicines may have side effects and for some people are incompletely effective.

Immunotherapy (Allergy Shots)

Injections are given frequently in scheduled doses of gradually increasing concentrations using extracts containing allergens to which the patient has specific IgE antibodies. The objective is to gradually desensitize the body to the offending allergens while ultimately diminishing the frequency of the injections. Ideally, an injection program can be discontinued after several years of therapy. Immunotherapy can be effective and should be considered only when the patient's test results, symptoms and clinical history have been carefully evaluated. There are important risks associated with immunotherapy that should be discussed with your physician. Food allergies differ from inhalant allergies due to different routes of contact and potentially greater exposure volume. Currently, immunotherapy is not an option so avoidance of the identified food that causes specific allergic symptoms is recommended. A small percentage of individuals develop severe, life threatening sensitivity to a single food and must avoid all contact for their entire life. Most food allergies are not so severe but are generally still best treated by avoidance. A carefully crafted elimination diet is used to confirm a food allergy. If the results are not clear, the best approach is a placebo controlled food challenge performed by an allergist in a medical setting and under direct observation of the individual when exposed to the possible food allergen.

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