Allergies
are
abnormal
immune
system
reactions
to
things
that
are
typically
harmless
to
most
people
.
When
you're
____________________
to
something
,
your
immune
system
____________________
believes
that
this
substance
is
harmful
to
your
body
.
Substances
that
cause
allergic
reactions
such
as
certain
foods
,
dust
,
plant
pollen
,
or
medicines
are
known
as
allergens
.
In
____________________
attempt
to
____________________
the
body
,
the
immune
system
produces
the
antibodies
to
that
allergen
.
Those
____________________
then
cause
certain
cells
in
the
body
to
____________________
chemicals
into
the
bloodstream
,
one
of
which
is
histamine
.
The
histamine
then
____________________
on
the
eyes
,
nose
,
throat
,
lungs
,
skin
,
or
gastrointestinal
tract
and
causes
the
symptoms
of
the
allergic
reaction
.
____________________
exposure
to
that
same
allergen
will
trigger
this
antibody
response
again
.
This
means
that
every
time
you
come
____________________
contact
with
that
allergen
,
you'll
have
some
form
of
allergy
symptoms
.
