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Allergy -
Manifestation of Environmental Nuances
By: Vini
Tandon
Our
daily life is a continuous interaction between our body and the physical milieu
enveloping us, food we ingest, the plants that grow around us, the animals and
their products we come across knowingly or unknowingly, the things we contact
every moment, whether sleeping or relaxing or travelling or preoccupied in our
profession. However, nature has provided an innate ability to each one of us to
recognize SELF and NONSELF, and the ability to discriminate between harmful and
non-harmful things amongst the non-self. Body defenses are always on an alert
and work constantly round the clock sensing, suspecting and reacting to these
environmental non-self things. Once the sensors sense or even suspect the
peculiar non-self surrounding, whether touched, ingested or inhaled, the body
initiates an involuntary cascading reaction using all or one of its defense
mechanisms and produces some recognizable response or symptoms to avoid or
remove the non- self substances. The response may be a non-specific
inflammatory response to the irritant or it may be a specific immunological
response produced by a specific antigen antibody reaction triggering either one
of the four recognized prototype hypersensitivity reactions, commonly grouped
as allergic reactions. Sometimes the reaction is directed not only against the
labeled and identified allergen, but also, against the other antigens sharing a
similar protein epitope, thus cross reacting with the preformed antibodies.
Allergy is a
broad-spectrum common-mean term, literally meaning "changed reactivity" and
scientifically synonymous with the Type I Hypersensitivity reaction. The other
type of Hypersensitivity reactions (Type II, III, IV) are just pedagogical
categorization attempted b) immunlogists to increase the understanding of
different immune reactions which could be provoked b) many antigenes. In
practice these types do not occur in isolation from each other and mostly
overlap.
Our
environment abounds with uncountable allergens- (known substances capable of
triggering specific antigen antibody hypersensitivity reaction merely by
contact or inhalation or ingestion) and many more haptens (substance capable of
inducing hypersensitivity reaction not by themselves alone but only after
combining with some non-allergens). Each individual is unique and so is his or
her response to these environmental irritants. The consequent allergic reaction
may produce symptoms in one or more or all of the systems which we all
encounter at one or the other time in our life.
The skin is
the most common organ which comes in contact with these irritants and produce
atopic dermatitis (eczema) or in response to a systemic irritants produce
urticaria (hives). The other common organs affected are the eye and nose
producing rhino-conjunctivitis and bouts of sneezing etc. Major insult and
irritation of the environmental allergens is borne by the respiratory system
which revolts and cries for help producing wheezing and asthma- now a major
health problem of our country. In our greed and ignorance, we tend to insult
our another lifeline system, the gastro-intestinal system that again produces
the stereotype reaction to these allergens might produce a Type IV
hypersensitivity reaction of anaphylaxis, which may become fatal if not
controlled in time.
These above
mentioned symptoms may be an outcome exposure to the various grass, weed and
tree pollens which float in the air we inhale, producing seasonal symptoms in
many individuals, which might be relieved or aggravated in different
geographical zones depending on the habitat. Another group of irritant is the
moulds and yeast, which might be ingested or float in the air we inhale and
irritate the exposed systems. The group of allergens available ubiquitously in
our environment is in the form of epidermal and animal proteins released as
dander's feathers, bird droppings or murine and vertebrate defecates. Of course
the list of ingested proteins is as long as one can think and includes almost
all proteins derived from the animal kingdom as egg, milk, fish etc and those
of the plant kingdom in cereals, fruits, vegetables, spices etc. The venoms of
the innumerable insects and reptiles in our environment are another potential
under odd and bizarre conditions and surroundings. Sometimes the therapeutic
drugs given in good faith may produce hypersensitivity reactions due to the
drug compound itself or hapten or the preservative or additive in the drug.
The reaction
to the exposure to the allergen depends on the type of reaction triggered, the
quantity of allergen exposure and pre-sensitization of the individual to the
allergen. At times the response is mild initially and go unnoticed till the
sensitization or the allergen dose reach a stage producing grave symptoms and
fatal reactions.
Some such
allergens are the occupational allergens, which might produce havoc in one's
life by its repeated or continuous exposure. The allergen may be a chemical
compound or metallic alloy, a plant protein or animal product. The list is
inexhaustible and every thing on earth can be included and enlisted.
Many of the
common plant derivatives, used in our day to day life at every step from
survival to pleasure to relaxation can be the culprits, provoking this unwanted
allergic reaction. The morbidity due to these allergic disorders is very high
and most manifestations are misunderstood due to poor degree of suspicion and
thus misdiagnosed and maltreated. It is important to rightly recognize them,
and avoid contact with the specific agents, if possible, to reduce daily
morbidity.
One may be
surprised that latex products made from the sap of Hevea
braziliensis
is
one of the
latest recognized allergens inflicting its havoc in our sophisticated lifestyle
obsessed by concerns for style, sanitation and spread of the dreaded AIDS
virus. This goes mostly unnoticed as the symptoms may be mild and simulate many
non-specific reaction, but at times the reaction is grave or may be fatal. It
may be an instant reaction or a delayed hypersensitivity depending upon the
sensitivity of the individual. The reason for this is the lack of awareness
amongst the users, who might get caught totally unwarranted at wrong corners
and fail to link the symptoms to latex.
Are we aware
of the wide use of latex products in our day to day life? Perhaps no. Well,
latex is used in small things like balloons and toys, baby-bottle nipple and
pacifiers, condoms and diaphragms, tyres and tubes, garden hoses and LPG
connectors. Another set of people in contact with latex are the medical and
paramedical staff wearing gloves, and patients wearing stretchable bandages and
medical tapes or those in critical operative and post-operative care with
anaesthetic tubing's, ventilation bags and intravenous lines. Even the small
day to day things like the socks, the shoe laces and other undergarments have
elastic made from latex.
The
sensitivity to these, varies from individual to individual and also on the
degree of exposure. Typically, the more contact one has with latex, the more
sensitive he or she may become.
The problem
is ubiquitous and perhaps linked to an epitope in the rubber protein. The
resemblance to these epitopes is observed in many other plant products and all
those who are sensitive to latex may display cross reactivity to these
products. It has been observed that these latex-sensitive people display
potentially life-threatening reaction to specific foods especially bananas,
avocados, water chestnuts and even peanuts.
The best way
to survive and avoid the unwanted reactions is to rightly recognize the culprit
and to avoid it as far as possible using other alternative things. The next
best is to recognize the reaction and take proper medication to limit the
reaction. As and when the facility for desensitization will become available,
it may be tried. But awareness is the KEYWORD. Take care for you might also be
an innocent unsuspected victim.
Dr. (Ms.)
Vini Tandon, M.D. (Pathology), is a medical scientist at 1/104, VishwasKhand,
Gomti Nagar, Lucknow |
