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Anaphylaxis
What is Anaphylaxis?
Anaphylaxis is a severe allergic reaction - the extreme end
of the allergic spectrum. The whole body is affected, usually
within minutes of exposure to the allergen but sometimes hours
later. Causes include food, insect stings and drugs........
Its a fact that in Austrailia more
people die from bee-stings (due to anaphalactic shock) than
from shark attack each year.
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Anaphylactic shock
Bee stings can also cause massive allergic
reactions
The sudden death of champion hurdler Ross Baillie has highlighted
the dangers faced by those suffering from extreme allergies.
BBC News Online examines "Anaphylactic Shock", the
name for any life-threatening reaction to a seemingly innocent
substance.
Anaphylactic shock is an extreme form of allergic reaction to
a particular substance, and is often life threatening.
In effect, the body's immune system,
which is there to tackle substances or organisms which are a
threat, such as bacteria or viruses, decides that something
harmless poses a great danger, and launches a massive overreaction
In extreme cases, large quantities of
an antibody called immunoglobin E are produced, which cause
a variety of effects on the body's cells and tissues.
In particular, it causes the body to
release an excess amount of histamine, a dangerous chemical.
The resultant, and usually very swift,
effects are muscle contractions and swelling, often closing
the throat, making it difficult to breathe.
Sufferers may also experience abdominal
pain, vomiting and diarrhoea. Immunoglobin E expands blood vessels,
causing a drop in blood pressure, which leads to fainting or
unconsciousness.
The most visible signs are often swelling
and rashes on the skin, or on the lips and tongue if it is a
food allergy.
Bites, stings, and jabs
A variety of substances can trigger this
massive immune response.
Among them are insect bites or stings,
food - commonly nuts, drugs like morphine or the dye injected
prior to X-raying. The horse serum used in the makeup of some
vaccines can also cause anaphylactic shock.
Many people suffer severe allergic reactions
to certain items, such as pet fur or pollen, but these symptoms
are rarely life-threatening, and can normally be treated with
anti-histamines - a treatment which reduces the amount of dangerous
histamine in the body.
However, these treatments take up to
an hour to reach the bloodstream, and true anaphylactic shock
requires immediate treatment with adrenaline injection.
Hormone makes body 'fight'
Adrenaline is the "fight or flight"
hormone, which is released naturally when the body is in a stressful
or dangerous situation.
It makes the heart beat faster, widens
the air passages in the lungs, and reverses the widening of
the blood vessels caused by immunoglobin E.
Most people who realise they have severe
allergy reactions carry a ready-filled adrenaline injector with
them at all times.
However, such is the speed with which
anaphylactic shock takes hold, even immediate treatment with
adrenaline is not guaranteed to save the victim's life.
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