• Allergy is define as “the abnormal or unusual
response to a substance by human body is
called allergy. OR
• The harmful reaction to the external
substances is known as allergy.
• The external substances are known as
• Allergy has been a medical specialty more
than 50 years, although symptoms of allergy
has been recognized for many years.
• The term Allergy was defined in 1906 by Von
Pirquet in describing a change or altered
reaction the body. When an individual
develops and unusual response to substance
or conditions that is harmless to other. The
individual is said to be allergic.
The first reference to allergic disease was
found in the papyrus Ebers in which asthma
and diseases owing to “autointoxication”
The writing of Hippocrates record the least 12
records of asthma, the first case of Hayfever
symptoms was recorded by Herodotus.
Cause of Allergy
• According to published figure half of the U.S.A
population suffering from sort of allergic
syndrome. The exact cause of the allergy is
still un determined. The reasons why an
individual exhibit allergic response to regweed
pollen and other do not understood.
• Based on genetic study, medical
immunological investigators generally agreed
that the tendency to be allergic is hereditary.
• In addition to it various other factors such as
emotional factors , atmospheric factors,
psychosomatic factors and chronic types of
infection. However, because the most
allergens are composed of plant or animal
matters, they merit consideration in a treatise
on natural products.
• Predisposing factors that make some persons susceptible to
• Hereditary tendency to allergic response.
• Dysfunction of the endocrine glands.
• Increased excitability of sympathetic and parasympathetic
• Absorption of toxic metabolic and catabolic substances.
• Hepatic dysfunction
• Psychic influences.
• Types of symptoms depend on the shock organ affected by
particular allergens and its path of entry to the body.
• These are antigenic substances capable of
sensitizing the body in such a way that
unusual responses occur in the
hypersensitivity individuals. Almost any
substances weather of biological, chemical or
synthetic origin, may prove to be allergens.
• The allergen concerned with the patients symptoms
must be antigenic; that must be capable of eliciting an
antibody response. The antibodies are special protein
molecule helps to neutralize the parasitic invaders and
protect the person from further exposure. If immune
system is not strong disease condition occur. The
reaction between antigen and antibody is called
antigen-antibody reactions. Some of allergens circulate
in the blood and other which become attached to the
cells of the nasal membranes (fixed antibodies), which
may either inhaled, eaten, injected or contacted to the
Types of Allergic reactions
• Allergic reactions may be of two types
• A. Localized reactions: If the state of shock is
confined to the area of the introduction of the
allergen, the condition is a localized reaction.
• e.g. when pollen grains are inhaled which
cause sinusitis due to allergic reactions. The
sinusitis is restricted to the face so allergic
reactions are localized.
• If it is extended beyond this area it may be
generalized or constitutional reactions.
• The constitutional reactions are produce in
the some patients by the injection of penicillin
preparations and extremely uncomfortable
and sometime dangerous and even fatal.
Mechanism of action of allergens
• Generally allergic reactions takes place in
• Primary Exposure
• Secondary Exposure & Release of mediators
• When the body is first subjected to the
allergen (antigen), the condition is referred to
as primary exposure. Because no antibodies
has been formed previously, no symptoms of
the allergy are produced during the primary
Secondary Exposure and release of
• However during the subsequent exposure, the
allergen contacts the antigen-antibody reactions.
• During secondary expose the antibody become
attach to the mast cells-white blood cells
(basophils), and form a complex and as a result
basophils burst due to antigen-antibody reaction
causes a liberation of histamine, bradykinin and
other mediators of allergic symptoms.
Types of Allergens
• Inhalant Allergens: substances that are
distributed in the atmosphere and contact the
nasal or buccal mucosa during respiration are
called inhalant allergens.
• Ingestant Allergens: Those that occur in the
foodstuff and are swallowed are known as
• Injectants Allergens: Those may be present in the
solutions intended for parenteral administration
are known as injectants.
• Contants Allergens: Those that come in direct
contact with epithelium.
• Infectants Allergens: metabolic wastes and
growth products of pahtogenic microorganisms.
• Infestants Allergens: Parasitic microorganisms in
or on the body.
• In addition to these materials allergy may be
caused by heat, cold, changes in climit, anger or
frustration (psychosomatic allergy) and others.
• Inhalant Allergens: substances that are
distributed in the atmosphere and contact the
nasal or buccal mucosa during respiration are
called inhalant allergens.
• Repetitive sneezing, release of watery fluids,
swelling of nose, itching redness and
lacrimation of eyes.
• The allergic reactions are localized because
the symptoms are restricted to face only.
Similar symptoms may appear in case of
• The allergic condition or condition of the body
is known as sinusitis (inflammation of sinuses
or nasal passage) or hayfever.
• Types of Hayfever:
• Seasonal Hayfever or pollinosis
• Non-seasonal Hayfever or perennial rhinitis
• SEASONAL HAYFEVER: the allergic symptoms
may be develop during certain season
(months) of the year. This condition is also
known as pollinosis because it is related with
the release of pollen grains from certain
• Types of seasons on the basis of pollen grains
• There are three pollen seasons
• The tree season, in spring which extends from
feb. to june.
• The grasses season, after spring or early
summer from april to Aug.
• The ragweed season in late summer from Aug.
to mid Oct.
Thus the season in which allergic symptoms
occur can be identified the types of pollens
grains responsible for the allergy.
Composition of Pollen Grains
• Pollen grains can be distinguished and
identified easily due to their heterogeneous
• They may be oval, round, annular, square or
rectangular in shape. The outer surface of
pollen grains is called “exine” while the inner
surface is “intine”. Due to shape and surface
appearance of exine, the type of specific
pollen grains may be identified.
The pollen grains may be spread through wind or
insects. So the pollens liberated through the
anemophilous plants are called atmospheric
pollens. These are wind pollinated pollens e.g.
pollens of tree such as oak and walnut, pollens of
grasses bermuda and timothy, pollens of weeds
such as ragweed and plantain.
The pollens liberated through entomophilous plants
(insects pollinated) are called insect pollinated
pollens e.g. pollens of clover, hollyhock and
• In case of non seasonal hay fever the allergic
symptoms may be developed through out the
year with out regularity. It is caused by
inhalant allergens other than pollen grains like
fungus spore, dust etc. it is also called
• The condition may be for a few days, then
disappear and reaper after few days or month
or some time it is not regular.
Causes of Non-seasonal Hay fever
• It is due to inhalant allergens at the place of
living or work. These allergens are:
• Cotton pillow cases: in home cotton may
cause allergy to hypersensitive person.
• Odor and perfumes: cosmetics contain volatile
oils which are inhaled and cause Hay fever.
• Animal Epidermis or Dander: the epithelial
scales called dandra of pet animals (cats, dogs)
also cause allergy or Hay fever.
• Castor beans: the castor oil seeds contains allergens in
the oil cake which cause severe allergy to the person in
industry (use castor beans).
• Fungus spores: the spores are produce by the fungi and
distribute in air and cause allergy when inhaled.
• Dust: it is mixture of different pollens, mold spores,
cotton, animal dander, and several other substances.
All these substances produce non-seasonal Hay fever.
• The test for dust allergy is difficult then other tests of
• Substances that are found in foods stuffs and
are swallowed are called ingestant allergens.
• When foods are digested and the nutrients
are absorbed, substances in the food
(ingestant allergens) stimulate allergic
response. These reactions cause a number of
• Food allergens ordinarily cause GIT symptoms, but they
may also cause
• Skin rash
• Puffed lips and tongue
• Bronchial asthma
• Severe cases of eczema of hands
• Atopic dermatitis (such as tomato rash, strawberry
rash, or that caused by eating chocolate, shellfish)
• In food allergy the activity of allergens is not
localized in one organ or area of the body, but
it is transferred to other organs by the blood.
Source of Ingestant Allergens
• Some of the most common allergens ingested by
children are foods considered essential to proper
diet and growth such as
• Cow’s milk, orange juice, cod liver oil, vitamin
containing fish liver oil.
• Hundreds of extracts of food stuffs are
commercially available as a single or multiple
units for use by the allergist or diagnostic skin
test materials, however, they have little or no
value in therapy.
• Milk Allergy: Milk allergy is a specific
immunologic, antigen-antibody response
owing partially to lactalbumin. This protein
acts as allergen and responsible for antigenantibody reaction. Because on heating or
boiling alter this protein and thus no
Symptoms of food allergy
• Milk allergy may result in
• Severe dermatitis
• Recurrent rhinorrhea
Various commercially milk substitutes that are
prepared from soybean isolates offer a milk-free
formula claimed to be devoid antigenicity.
Two of these are Soyalac and Prosobee
• Coffee Allergy:
• It has been determined that coffee can produce allergic
• Symptoms of Allergy:
• Severe migraine, gastroenteritis and widespread hives
• The principal water-extractable allergenic component
of green coffee is chlorogenic acid (3-caffeoylquinic
acid). Some of authorities disagree with this, calming
that the coffee roasting process alters its structure.
• Treatment: the main treatment of this type of
allergy is to remove that material from food,
which cause allergy or hypersensitivity
• All the allergens are available in the form of
extracts, which are obtained from food. These
allergens are injected to the hypersensitive
person, if he response, he will avoid to take
• The injectants (injectable preparations and
insects) cause allergy in a hypersensitive
person, allergic condition is known as
Source of injectant allergy
• Insects as source of natural injectant allergens
• Injections: Allergic reactions to penicillin
injections are well known to most of the lay
public. Anaphylactic reactions to penicillin occur
with a frequency of 1-5 per 10,000 patientcourses of penicillin.
• Skin test for penicillin allergy is of definite value,
but test must be conducted under control
• 6-Amino penicillinic acid (6-APA) and 7Aminocephalosporanic acid (7-ACA), as well as
semisynthetic penicillin's and cephalosporin,
cause positive intra-cutaneous reactions in most
• For this reasons, such antibiotics as the
cephalosporin's and semisynthetic penicillin’s
should be used with caution by the physicians
treating patients that are sensitive to penicillin G.
• In addition to penicillin products, other
injectables may cause allergies such as liver
extract, antitoxins, and the glandular
• Allergic reactions:
The allergic reaction is generalized in case of
injections, because the injectant allergens enter
the blood stream and circulate throughout the
• Symptoms: the symptoms in each case are
similar to those of the antibiotics;
• Itching of the plasma of the hands and the
soles of the feet
• Erythema (redness of skin)
• Peeling of skin are characteristic.
• Insects as source of natural injectant
• Bees, hornets and wasps such insects are
considered as source of injectant allergens.
• Stings of such insects can induce severe
reactions. In fact it has been estimated that
more people die annually from bee sitting and
wasps sting than from snakebites.
• Such patient can be immunized by using
injections of antigens because one antigen is
common to all bees and wasps.
• Research is being conducted on this subject at
the present time. Whole insects extracts have
been made to determine the optimal method
• Bitting arthropods are also subjected to
clinical trails among these spiders, mites, lice,
chiggers, ticks, sand flies, horse flies,
scorpions, centipedes and numerous others
indigenous to geographic areas are
• Allergic reactions: stings of insects can induce
severe local and constitutional reactions
sometimes causing death.
• Allergens that come into direct contact with
the epithelium are called contactant allergens.
• The contactant allergens cause a localized
reactions in a particular part of the body.
• Symptoms: The allergic symptoms of the
contactant allergens are watery blisters and
• Watery blisters: These are white in center and
surrounded by red color, associated with
pruritis (itching), due to which patient desire
to scratch the blisters. The blisters break open
and the exuding fluid forms new blisters that
spread quite rapidly.
• Source or causes of contactant allergy: there
are many substances and products, which are
identified as source of contactant allergies,
• Plants or plant products
• Cosmetics and perfumes etc.
Plants or plant products:
• Many substances and products has been recognized as the
cause of contactant allergies.one of the important of this is
Poison ivy, Toxicodendron radicans(L) Kuntze, other
allergenic species of the genus Toxicodendron include
T.diversilobum (T&G) known as western poison oak,
T.quercifolium (Michx) known as eastern poison oak etc.
• All these contains the same nonvolatile, phenolic principle
urishiol resin, and mainly cause watery blisters.
• Oak: a cupuliferous tree of genus Quercus. The bark of all
species contains a large proportion of tannins.
• Quercus: galls for dye and ink
• Other plant excitants such as asparagus
(antiseptic), buckwheat, catalpa leaves
(asthma), daffodils, English ivy, ginkgo leaves,
lobelia (tobbaco), mayapple, osage orange,
smartweeds and dozens of other cause
• Occasional contactant dermititis has been
caused by aeroallergens.
Various pollen grains that contain oils, hairs
from different kinds of leaves and flowers, and
even small fragments of plant tissue carried by
smoke from bush fires, grass fires and burning
leaves cause contactant allergy.
Cosmetics and perfumes:
• Cosmetics manufacturing companies remove
some known irritants and allergens from there
beauty products and consequently use the
term hypoallergenic cosmetics to denote this
• An ingredient in “violet” talcum powder is
chief source of allergy. Dibromofluorescein,
commonly used in lipsticks is another.
• Perfume, soaps and soaps powders, plain
detergents, enzyme detergents, nail polishes,
nail polishes removers, hair dyes and hair
sprays, blankets, wool in clothing are the
numerous major causes of contactant
• The bacterial metabolic wastes are considered
as infectant allergens.
• Numerous living organisms may cause allergy
through the products they release during their
metabolism in the human body.
Source or Cause of infectant allergy:
• Many microorganisms or pathogens certain
types of bacteria, protozoans, molds,
helminthes, and other parasitic forms by the
presence in the body for long time responsible
for chronic illness.
• Metabolic products of growth of these
organisms may be of such nature that the
individual become sensitized.
Bronchiectasis: an example of infectant allergy:
The chronic bacterial infection of the
bronchioles, where in the constant presence of
bacterial wastes may sensitize the allergic
individual is the one of the example.
The person may exhibit the allergic symptoms
but does not respond positively to skin tests for
• In a manner somewhat similar to the
infectants, parasitic organisms may sensitize
the human body.
• Invasions of hookworms, tapeworms,
pinworms, threadworms, dermatophytes and
other forms have caused allergic response in
• Growth products and metabolic wastes of
these parasites are constantly present in the
body and referred to as infestant allergens.
• To determine the circumstances surrounding
the patient’s allergy, the allergist must record
all the details regarding the allergic attacks,
including data on the type of occupation and
the familial background. All the information's
concerning with patient like mode of onset of
past symptoms, cause of recent attack is
recorded in the case history.
• A stated on a typical case history report, the
• Name and sex
• Marital status
• Chief complaint
Age of onset (time of development of symptoms)
Date of first attack
Place, time and mode of onset
What relieves attack
Date of onset i.e. when the symptoms developed
Place of onset i.e. where the symptoms develop
Mode of onset i.e. how the symptoms develop
• Symptoms affected by:
Smoke or fumes
Time of day
Moving in lawn
Change of season
Change of environment
Change of occupation
• Other points of information include the types
of medication the patient may take and
condition of home environment (heating
system, type of floor covering, presence of
house mold pests, nature of bed cover and
pillows etc). A past medicine history may be
requested. Allergic symptoms of the paternal
and maternal relatives are frequently a clue.
• A complete case history includes both a
physical and a laboratory examination, the
latter to include reports of urine, blood,
sputum, and nasal smears. In addition, results
of radiograph and electrocardiogram are
customary. Following lab tests the allergist
makes his diagnosis and attempts to confirm it
by the use of skin tests.
• Skin tests are conducted in 2 principal ways
• 1. Scratch test: it is similar to smallpox
vaccination, i.e., scratching the skin and
introduce an extract of the allergic substances.
• 2. intradermal(intra-cutaneous) tests: in which
a small quantity of the extract is injected
between the layers of the skin.
• Allergenic extracts are stable preparations of
various antigenic substances and are used for
diagnosis, pre-seasonal prophylaxis and
treatment of allergies (except food allergens).
• In each case allergenic extract represents a
solution of the chief constituents of the tested
material. (preparation of extracts involves the use
of one of several standard extracting fluids.
Coca’s fluid, normal saline solution, purified
water, dilute glycero-dextrose solution etc ).
• By injecting small amount, usually 0.1ml, into
the arm of the patient, the allergist can
observe the resulting reaction within 20
minutes and classify it using the scheme.
• A skin test, then, is actually a localized
reaction that determines whether the patient
responds to the particular allergen. skin test
are quite useful in determining sensetivity to
inhalant, injectants, contactants and some
ingestants although the reactions in ingestants
are less reliable.
• Normally contactants are applied as patch
test, where the material is applied directly to
the skin which is neither scratched nor
penetrated with a needle. As a general rule,
patch test require a much longer time for the
reaction to occur at least 48 hours but
sometime 4-5 days.
• Other tests, such as ophthalmic test,
microscopic examination of nasal secretions,
passive transfer test employed by physician as
Clinical designation of skin reactions
No reaction or no different than control
No appreciable difference from control
other than slight erythema
Erythema smaller than 20mm in
Erythema larger than 20mm in diameter
but no wheal
Definite wheal with surrounding
Wheal with definite pseudopods and
Allergy may treated by several ways
Removal of allergens
Avoiding of suspected foods
Immunotherapy or hyposensitization
• It is a type of treatment in which the allergist
suggests a serious of injections of offending
• These injections are known as allergy shot. They
are injected at regular intervals. For safety
reasons, the injections begins with small
allergens dose, the amount of allergens increased
weekly, until a high dose of injected allergens are
reached. These injections or allergic shot
desensitize the patient to the allergens due to
which the allergic response is reduce.
Purpose of immunotherapy
• The purpose is to produce blocking or
neutralizing antibodies. These antibodies
provide a protective response in the cells. As a
result allergens are prevented from
• When this blocking is achieved then little or
no histamine is released due to which allergic
symptoms are reduced.
• Example of pollen allergy:
• If the patient has a case history of allergy and
have exhibits a positive reaction to ragweed
pollen extract, the allergist will probably resort to
the hyposensitization method of treatment.
• At regular intervals a measured amount of diluted
extract is injected subcutaneously. The dose is
gradually increased until the patient can
withstand the inhalation of the normal seasonal
atmospheric conc: of regweed.
• Complete freedom from is rarely
accomplished because of inadequacy of the
• In addition because the identity of allergenic
fraction has not been established chemically,
it can not be assayed in the completed extract.
• Pollen extracts are made on the wt, volume basis and are
standardized according to the no. of pollen units, protein
nitrogen unit or depending on the laboratory policy.
• One pollen unit represent the activity in 0.001 mg of
• Most of researcher has concentrated on ragweed, although
it has numerous advantages. Much of this researchers
involves the use of selective extracting fluids. Such as
preparation of alum-precipitated and ammonium sulfate
treated extracts the application of chromatographic and
electrophoretic means of analysis.
• If the treatment is conducted prior to the time
of pollination of the plants it is termed as preseasonal.
• If maintained throughout the year for some
allergy is called perennial
• And if instituted during the symptomatic
period is called co-seasonal.
Effectiveness of immunotherapy
• Allergen immunotherapy is effective in
overcoming stinging insect allergies. These are
dangerous allergies and if it is untreated can
result in fatal allergic reactions. The patient is
given small injections every 20-30 minutes for at
least several hours. As a result immunity is
developed with in 10-14 days. This type of
immunotherapy is also effective for severe hay
fever and also in chronic allergic asthma.
• It is also useful for contactant allergy.
• For most of the patients having allergies,
medicines are used to begin therapy, for example.
• Most forms of hay fever are easily controlled with
antihistamine drugs. The antihistamine only
prevent the release of histamine. The could not
prevent the antigen antibodies reactions.
Antihistamine relieves symptoms such as itching,
and sneezing produce by histamine.
• Asthma is usually treated with medications taken
orally are inhaled in vapor form. Asthma
medications includes bronchodilators and antiinflammatory steroids, which inhibits the immune
response that cause air-way inflammation.
• In case of anaphylactic shock emergency
treatment with an injection of adrenaline also
called epinephrine is required. This injection
quickly widens blood vessels and open up
Removal of allergens
• In many cases the best treatment of the allergy is
removal of the offending allergens from the
patient environment, if possible. If pet animals
are the case of allergens then the effective is to
remove that pet animal. Although the patient
also given desensitizing injections containing
extracts but most easy way is to remove animals
which case allergy.
• Some allergens such as plant pollens are
impossible to remove because they flout freely in
Avoiding of suspected foods
• Food allergens are difficult to diagnose and
treat than other allergens, because skin test
are un reliable and blood tests may be
doubtful. Therefore when a particular food is
suspect i.e. is allergenic to the patient, then
the patient should avoid it. If the patient does
not know about the allergenic food, the
allergist will suggest a special diet to the
patient. This diet is simple and free from
• After this the allergist will reintroduce each of
the foods one at a time to identify that which
type of food acts as offending allergens. When
this food is detected, the patient is advised to
avoid such food.
Allergy may develop at any age
report of the patient receiving medical attention in survey of
Asthma & Hay fever
65 and over
Is the hereditary factor important
When both parents are allergic
75% of offspring may develop allergy
When one parent is allergic
25.50% of offspring may develop allergy
When neither parent is allergic
7.12% of offspring may develop allergy
• The durham sampler method is used to
determine the pollen count is the gravity
method in which a microscope slide is rubbed
with a petrolatum mixture and is exposed in a
standard exposure device for 24 hour period.
• The pollen count represent the number of
pollen grains per square cm of slide surface.
• The pollen must contain an excitant of hay
• The pollen are anemophilous or wind borne.
• They are produce in large quantity.
• The plant producing the pollen are widely
• The American Academy of Allergy has
established a chart for the ragweed index of
the principle cities.
Trees: the spring flowering trees may be
subdivided into early and later spring.
Early spring trees:
Ulmus americana L
Acer rubrum L
Populus deltoides Marsh
Later spring season:
Betula papyrifera Marsh
Betula lenta L
Juglans nigra L
Grasses: the most important grass of U.S are
Anthoxanthum odoratum L
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