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Diet For Allergy Sufferers

A. Overview Of Allergies

Etiology of Allergies

The term allergy was first coined by Clemens Von Rirquet in 1906 to describe an altered or

changed reactivity of the immune system to foreign proteins, irrespective of whether this resulted in

immunity or a harmful effect. However, today most clinicians restrict the use of the term to situations

where an exaggerated sensitivity (hypersensitivity) result form a heightened or altered reactivity of the

immune system in response to external substances. These foreign substances that provoke allergies are

called allergens and enter the body either by inhalation, swallowing, injection, or contact with the skin,

eye or airways. The Royal College of Physicians reported that common allergens include grass, weed an

tree pollens, substances present in house dust, fungal spores, animal products, certain foods, and various

chemical agents found in the home and at work. Allergy is not a disease but a mechanism which may play

a role in a number of disorders.

Pathifisiology and Allergic Mechanism

1. Atopic (IgE-mediated) allergy

Atopic allergic conditions arise when individuals produce increased amounts of the allergic

antibody immunoglobulin E (IgE), a type of antibody which binds particularly strongly to

specific receptors on mast cells. When the cell-associated IgE comes into contact with the

specific allergen against which it is directed, the molecules of IgE become cross-linked by

that allergen and the mast cell becomes activated. This result in the release of inflammatory

chemical such as histamine and leukotrienes.

The majority people who suffer from IgE mediated allergy are said to be atopic. That atopic

individuals are more likely to develop these allergic conditions than non-atopic individuals.

However, not all atopic individuals do so. Atopy is associated with disorders discussed in this

report are mainly atopic in nature, so when the term allergy is used in an unqualified way, it

refers to atopic allergy.

2. Non-atopic (non-IgE-mediated) allergy

However, allergy is not as simple as this brief summary seems to suggest. Some conditions

are not dependent on IgE but still involve an abnormal immune response to a wide variety of

external environmental agents. These conditions are known as non-atopic (non-IgE-mediated). The mechanisms of non-atopic disease are less clearly understood but some

disorders may involve a different subset of immune cells known as T helper 1 (Th 1).

Sign Symptoms of Allergies

1. Acute symptoms of allergy such as sweezing, spasm of the airways, itching, rash and tissue

swelling are caused by histamine and when tehere is a large release into the circulation, as in

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anaphylaxis, histamine cause a fall in blood pressure. Leukotrienes have a more prolonged

course of action, causing airway narrowing and swelling which leads to shortness of breath

and wheeze.

2. The symptomps of chronic allergic disorders, such as a continuous blocked nose or on-going

wheeziness may result from another molecular pathway involving immune cells known as T

helper 2 (Th 2) cells.

The Types Of Allergies

1. Allergic rhinitis

2. Asthma

3. Anaphylaxis

4. Allergy to insect venom

5. Drug allergy

6. Food allergy

7. Oral allergy syndrome

8. Urticaria and angioedema

9. Atopic dermatitis (atopic eczema)

10. Multiple allergies

11. Sensitisation and allergy symptoms

Allergy Tests

When a persons medical history shows that allergy might be a cause of the symptoms, then tests

can either pinpoint or rule out various cause. This history also needs to be taken into account when any

tests are interpreted. There are three medically accepted tests, which can be helful when used properly.

1. Skin prick test

The skin prick test is probably the must commonly used allergy test. Twenty-five allergens

can be tested in one session. Allergens are selected according to the medical history. The tests

can be carried out on any age group, including babies, and are very safe.

2. Blood test

This test measyres the amount of IgE allergy antibody (in a blood sample) for a suspected

allergen. So, in a person suspected of being allergic to eggs, a doctor would ask for IgE to

egg. A blood sample can be taken at your GP surgery or at a hospital. Blood is usually taken

from a vein in the arm, using a fine needle and small syringe. The sample is sent to a central

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laboratory. Typically, results may not be available for few weeks because testingin batches is

most cost-effective.

3. Skin patch test

This test is very different from the tests discussed above. Patch tests are especially useful in

certain types of slow onset reactions, typically eczema. This test involves placing several

circular test patches on the patients skin, usually on their back. After two days, the patient

must return to the hospital clinic for patch removal and test interpretation. The test tent to be

done in specialist hospital clinics dealing with skin problems because the results can be

complicated and difficult to interpret. They are only useful for allergies involving slow onset

rashes. By and large, these tests are not useful in cases of skin allergy occurring immediately

on contact with an allergic trigger.

B. Nutrient Management

Dr. Graham Denereux, Consultant at the Deparment of Environmental and OccupationalMedicine, University of Aberdeen, told us that maternal ingestion of nutrients, particularly vitamin E,

posibly vitamin D and even zinc could conferprotection against allergies in the child.

An increased risk of asthma and atopy also appears to be associated with a low intake of fruit,

vegetables, fish, butter, dairy fat, antioxidants, magnesium and n-3 fatty acids, and a high intake of

sodium, margarine and n-6 fatty acids.

Professor Warner told us exclusive breastfeeding for at least the first four months of life reduces

the rates of early food allergy and eczema. However, a longer-term protective effect in later allergic

manifestations is less evident.

The role that food allergen consumption plays during early life is still uncertain, although there

has been some suggestion that early exposure to allergens such as peanuts may protect against allergy.

REFERENCES

1. Science and Technology Committee . 2007.Allergy . London : Authority of the House of Lords

2. Lay Advisory Committee . 2005 .Allergy and Allergy Tests A Guide for Patients and Relatives .

London : The Royal College of Pathologists

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