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					“Allergies”                                                                                              1


                                                 Allergies



          Outline

    -     Introduction/Overview
    -     Types
    -     Causes & Risk Factors
    -     Signs & Symptoms
    -     Stages: (if applicable)
    -     Medical Tests & Diagnosis Methods/Tools
    -     Treatment Options
    -     Prevention Methods



                                        Introduction/Overview

          Allergies and other type of immune hypersensitivities are important undesirable side effect

of our immune system. These problems occur in people who have a specific allergic tendency.

Anyone suffering from allergy can take comfort that there are over 50 million fellow American

sufferers of this problem. Roughly one in 6 American is afflicted with allergic problem.

Fortunately, in very few people allergic condition can become life threatening. In most allergy

sufferers problems due to allergy appear to be trivial such as runny nose, sneezing, itchy eyes, sinus

problem, rash and skin complaints but these otherwise minor problems can make the allergy

sufferers lives quite miserable.

          Our immune system, essential for defending our bodies against foreign organisms, produces

antibodies and activated white cells to attack invaders like viruses and bacteria. Occasionally, the

immune response results in an inappropriate or exaggerated reaction called hypersensitivity.

          Hypersensitivity is classified into four types; Types I, II, III and IV. Types I to Type III

hypersensitivities are antibody-mediated while Type IV is a cell mediated hypersensitivity. Type II

& III are Immunoglobulin G (IgG) mediated while Type I sensitivity is Immunoglobulin E
“Allergies”                                                                                             2


mediated. The term „Allergy‟ is confined to IgE mediated reactions or Type I hypersensitivity

[Levinson, 2004] .

          Immunoglobulin E (IgE) is our body‟s host defense system against certain parasites such as

worms. In developed countries, where parasitic infection is uncommon, most people have no or

very low level of IgE. An allergic reaction or allergy occurs when our body‟s immune system

mistakenly considers a harmless substance, called „allergen‟ as dangerous and starts producing IgE

to trigger an allergic reaction [Levinson, 2004].

                                           Types of Allergies

Allergic Rhinitis:

          This type of allergy causes swelling of nasal mucosa with respiratory discomforts like

sneezing and runny nose by inhaling allergens such as pollen, molds, dust, dander and other

allergens.

Allergic Conjunctivitis:

          The allergic reaction affects the eyes, redness and itching are the signs of this allergy.

Bronchoconstriction:

          Wheezing and shortness of breath caused by narrowing of bronchial cavities. Asthma is a

serious type of bronchoconstriction. This type of allergy is also caused dust, pollen, mites, and other

allergens.

Ear Allergies:

          The allergens affect ear passages causing pain and impairing hearing.

Skin Allergies:

          Itchy rashes, blisters, hives, and contact dermatitis caused by touching certain substances

such a poison ivy or food items are manifestation of this type of allergy. In allergies where swelling

occurs as a result of hives, swelling can cause breathing and swallowing difficulties.

Food Allergies:
“Allergies”                                                                                               3


          Certain kind of foods, such as fish egg, nuts and milk can cause intestinal upsets due to

allergic reactions.

Time Delayed Allergies:

          An allergic response appearing hours or days after application or absorption of an allergen;

including contact dermatitis and bacterial allergy [Allergies, 2006]

Anaphylaxis:

          This is the most severe systemic allergic reaction causing bronchoconstriction, swelling of

body tissues, vomiting, cramps, skin reactions and drop in blood pressure, coma and even death

[Guyton & Hall, 2006].

Allergy can also be classified on the basis of its effect and allergen as:

                       Respiratory Allergies

                       Skin Allergies

                       Food Allergies

                       Asthma

                       Drug Allergies

                       Sting Allergies

                                       Causes & Risk Factors

          Problems with normal immune responses are believed to be the result of both genetic and

environmental factors. Children of allergic parents are more likely to have similar allergies though

the allergens may differ. [Allergies, 2006] Genetic research is leading scientists to believe that skin

and tissue specific genes may be responsible for causing allergy symptoms [NIH, 2000]. Stress and

anxiety are acknowledged a common cause of allergic reaction. [Lenzoff, 1997] subjected patients

suspected of multiple chemical sensitivities concluded that in some sufferers allergy symptoms

might be triggered by their perception of an environmental insult.

          Increasing use of chemicals has resulted in introduction of new toxins into the atmosphere.

The increase in number of allergy cases during the last decades is often attributed to atmospheric
“Allergies”                                                                                              4


pollution [Bornehag et al, 2004]. Better identification of problem as allergy and not other minor

condition such as cold is perhaps also responsible for increased numbers.

Allergy or Cold

          A number of symptoms of common cold are also the symptoms of allergy. It is not unusual

to mistake one for the other. The major difference between the cold and flu are [Allergy, 2006b]:

              -   Both cold and allergy show the common symptoms of allergy but the cold is also

                  accompanied by fever and pain.

              -   Allergy begins immediately after exposure to the allergen while cold takes a day or

                  more to develop to full strength.

              -   Cold is a self terminating diseases and the symptoms disappear in 3 to 7 days while

                  allergies continue till the person remains exposed to the allergen

Allergens

          The body‟s immune system has the capability to attack a foreign organism. If it identifies a

substance such as pollen as foreign, even mistakenly, the defense mechanism comes into action and

IgE is produced to fight off that particular substance. Thus, there will be separate IgE for pollen and

for dust allergies. There are many allergens as any person could be allergic to a common substance,

which is not an allergen to others, but the common allergens include pollen and fungus from weeds,

grasses. Trees and outdoor mold, dog and cat dander, dust particles, noxious vapors and smog,

foods such as fish, eggs, nuts and insect bites.

                                            Signs & Symptoms

     In addition to the usual sneezing, runny nose, rashes allergy and red or itchy eyes symptoms

include atopic dermatitis, contact dermatitis, headache, earache, hives, coughing, sinusitis, and other

discussed above.

                               Medical Tests & Diagnosis Methods/Tools

The diagnostic tests for Allergy include:

                     Skin Prick Test (SPT)
“Allergies”                                                                                                  5


                   Total IgE Test

                   Range of Specific IgE Test

                   Phadiatop Assay

                   Specific IgE Pediatric Food Mix fx5

Skin Prick Test:

          Skin prick test is a common and simple method of diagnosing allergy. In this test small

amount of suspected allergens are injected either intra-dermally or into the scratching made in the

patient‟s skin. Patient allergic to any of the allergen shows a visible inflammation after half an hour.

          Skin Prick Test (SPT) only responds to allergens used in the test. In cases where patient is

allergic to any other allergen, this test will not show. Some patients with delayed type

hypersensitivity may be adversely affected by the test.

Total IgE Test:

          Patient serum IgE test is another method used for determining Type I hypersensitivity. The

test provides useful indication for allergy. This test however is not considered conclusive. The test

measures total IgE value and is said to be only to report existence of allergy 60% of the time

[Labspec, 2006]. The extent of symptoms and type of allergy has an effect on the result. Severe skin

allergy shows a higher IgE value than rhinitis or conjunctivitis. [Labspec, 2006] also point out that

Standard IgE values appear to vary with ethnicity of the patient.

Range of Specific IgE Test:

Some diagnostic suppliers are manufacturing specific IgE test for allergens. Specific tests for over

400 allergens are available. Some of these specific tests have been approved for routine tests, other

are awaiting approval. [Labspec, 2006]

Phadiatop Assay:

          Instead of testing total IgE or specific test for a single allergen, this test tests serum for a

wide range of inhalant allergens. The test is said to be 95% reliable and can be used to exclude

allergens included in Phadiatop assay.
“Allergies”                                                                                                6


Specific IgE Pediatric Food Mix fx5

          His test is similar to Phadiatop Assay, but instead of inhalant allergens, ingestant allergens

are tested. This test is still in approval stages for general laboratory use.

                                            Treatment Options

Many people with mild allergies avoid seeking medical help, but it is important to know that

allergies if left untreated can develop into serious health problems like infections in sinuses, throat

and ears, chronic respiratory problems, skin problems such as eczema. The treatment Options for

allergies include:

                         Avoid allergen environment and/or food

                         Over the counter medication (histamines)

                         Prescription drugs & nasal drops,

                         Allergy shots

                         Allergy Drops

                         Immunotherapy

                         Alternate Therapies

          Once a person knows the substance that causes allergy, the best treatment is to avoid that

substance. However avoiding allergen is not always possible as it is not possible to breathe. Food

allergens can be easily avoided [When Should I Get Medical Treatment for Allergy, 2006] .

          In a very large number of cases of mild allergy over the counter medication is all one needs

to relieve the symptoms. It is important to consult a doctor for over the counter medicine too, as

some of these medicines if used excessively can cause serious side effects. Most of the histamines

cause drowsiness.

          Antihistamines and decongestants relieve the symptoms of most allergy sufferers. Again, a

physician‟s advice should be sought. Many new antihistamines relieve the symptoms of allergy

without causing drowsiness. In sinus congestion, nasal sprays available on prescription provide

quick relief from symptoms of allergy.
“Allergies”                                                                                             7


          Allergy shots prevent the allergen from being recognized as a foreign body. This treatment

is becoming very popular. Sublingual drops also known as sublingual Immunotherapy (SLIT) is an

alternate to allergy shots and has the same principle of desensitization. Oral application of SLIT is

also considered convenient by the patients.

          Those interested in alternative medicine often recommend several alternate therapies.

Dietary supplements are said to increase health of immune system and prevent allergies. The other

alternative medicines are beyond the scope of this paper. [Allergies, 2006a] provides several

references to alternative treatment websites.

          Anaphylaxis must be considered a medical emergency and immediate medical help must be

sought as it can cause low blood pressure, hyper-constriction, coma and even death.

                                          Prevention Methods

The best prevention is to avoid the allergen responsible for causing the allergy. Cross the counter

medicine approved by a patients physician may also be used before coming into contact with

allergens. In view of the number of sufferers, various equipments such as vacuum cleaners,

humidifiers, beddings and air purifiers are available in the market to control domestic allergens. A

physician may be able to advice about prevention methods about other specific allergies.
“Allergies”                                                                                             8


                                            Bibliography

     1. Allergies, (2006a), Alternative Allergy Treatment Options, [Online], retrieved from Internet

          on 10 January 2007,

          http://allergies.about.com/od/alternatives/Alternative_Allergy_Treatment_Options.htm

     2. Allergies, (2006b), [Online], retrieved from Internet on 10 January 2007, http://www.med-

          help.net/Allergies.html

     3. Allergy, (2006), What is Allergy, [Online], retrieved from Internet on 10 January 2007,

          http://www.setel.com/~allergy/Products/allergy

     4. Bornehag C, Sundell J, Weschler C, Sigsgaard T, Lundgren B, Hasselgren M, Hägerhed-

          Engman L (2004). "The association between asthma and allergic symptoms in children and

          phthalates in house dust: a nested case-control study.” Environ Health Perspective 112 (14):

          1393-7.

     5. Guyton, AC, and Hall, JE, (2006), Textbook of Medical Physiology-11th Edition, Published

          by Elsevier, Pa., ISBN 13-81-8147-920-3

     6. LabSpec, Allergy Diagnostic Tests, (2006) [Online], retrieved from Internet on 10 January

          2007, http://www.labspec.co.za/diag.htm

     7. Levinson, W., (2004), Medical Microbiology & Immunology, 8th Edition, McGraw Hill

          Companies, ISBN 0-07-143199-3

     8. Leznoff. A., (1999), Provocative challenges in patients with multiple chemical sensitivity, J

          Allergy Clin Immunol 1997 Apr; 99 (4):438-42

     9. NIH- National Institute of Health/ National Institute of Allergy and Infectious Diseases

          (NIAID), (2000), International Team Accelerates Investigation of Immune-Related Genes,

          [Online], retrieved from Internet on 10 January 2007,

          http://www3.niaid.nih.gov/news/newsreleases/2000/ihwg.htm

     10. When Should I Get Medical Treatment for Allergies?, (2006) [Online], retrieved from

          Internet on 10 January 2007, http://health.howstuffworks.com/allergy-treatments-ga1.htm

				
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