What
happens when you get an allergy?
An allergic reaction
starts when the body’s natural
defence mechanism - the
immune system - encounters a substance
and reacts in an inappropriate and excessive way. The
immune system, of course, is vital in protecting the
body against infection by destroying invading viruses
and bacteria. In an allergic reaction, a part of this
defence mechanism springs into action even though the
substance that acts as a trigger poses no real danger
or threat at all. The initial allergic response sets
up inflammation - part of the defence process - and this,
in turn, produces the typical signs and symptoms associated
with allergy.
To find out more about the body’s
natural defence mechanism, the immune system>
Before an allergic reaction can start, the immune system
must first recognise the trigger substance. This can
only happen after an initial contact has familiarised
the body with the trigger.
In order to explain how this works,
we’ll take
as an example someone who is allergic to a particular
type of pollen -
the sort produced by oak trees. The first time this
person came into contact with oak pollen,
there would have been no allergic reaction, no inflammation
and no symptoms of allergy. However, something was
going on inside the body. In response to the encounter,
a particular
type of white blood cell had identified the oak pollen
as a potential threat and set about producing special
chemicals called antibodies.
These would have the ability to attach themselves to
oak pollen if this substance
ever entered the body again.
For more detail on how antibodies
and allergy triggers switch on an allergic reaction>
The individual has become ‘sensitised’ to
this particular pollen. Because this sensitisation makes
them react in an excessive way to future exposure, they
are described as ‘hypersensitive’. The next
time oak pollen is encountered, the specific antibodies
will bind to the pollen creating a particle that will
set the body’s defences in motion to quickly produce
an allergic reaction. For more information on chemicals
and cells involved in creating allergic symptoms>
Early and late phase symptoms
The allergic reaction can produce a very rapid 'early
phase' response
from the body
and a slower 'late
phase' response that can
last long after the exposure to the trigger.
Find
out more information on how the chemicals and cells
involved in an allergic
response
interact>
Coping with your airborne
allergy>
What triggers your airborne allergy>
Treating your airborne allergy>
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