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House
Dust Allergy
House
dust allergy is common even in clean homes. It is a major
cause of year-round runny or stuffy nose, itchy, watery
eyes and sneezing for allergy sufferers. Dust can also make
people with asthma experience wheezing, coughing and shortness
of breath.
<>Why
does house dust cause allergic reactions?<>
House dust is a mixture of many substances. Its content
varies from home to home, depending on the type of furniture,
building materials, presence of pets, moisture and other
factors. A speck of dust may contain fabric fibbers, human
skin particles, animal dander, microscopic creatures called
mites, bacteria, parts of cockroaches, mold spores, food
particles and other debris. Of these, animal dander, house
dust mites, and cockroaches are the most common culprits.
A person may be allergic to one or more of these substances,
and, if exposed to the dust, will have an allergic reaction.
Is
dust allergy a sign of a dirty house?
No. A dirty house can make a house dust allergy problem
worse, however. Normal housekeeping procedures may not be
enough to get rid of house dust allergy symptoms. This is
because many of the substances in dust cannot be removed
by normal cleaning procedures. For example, no matter how
vigorously you dust or vacuum, you will not reduce the number
of dust mites present deep within carpeting, pillows, and
mattresses. Vigorous cleaning methods can put more dust
into the air making symptoms worse.
What
are dust mites?
Tiny microscopic creatures called dust mites are an important
cause of allergic reactions to house dust. They belong to
the family of eight-legged creatures called Arachnids. This
family also includes spiders, chiggers and ticks. Dust mites
are creatures that live well and multiply easily in warm,
humid places. They prefer temperatures at or above 70°F
with a relative humidity of 75-80 percent and die when the
humidity falls below 40-50 percent. They are rarely found
in dry climates.
People
who are allergic to dust mites react to proteins in the
bodies and faeces of the mites. These faecal particles are
found in the highest concentrations in pillows, mattresses,
carpeting, and upholstered furniture. They float into the
air when anyone vacuums, walks on a carpet or disturbs bedding,
but settle out of the air once the disturbance is over.
Dust mite-allergic people who inhale these particles frequently
experience allergy symptoms. In fact, a dust mite allergic
patient who sleeps for 8 hours every night spends one third
of his life with his nose in direct contact with a pillow
loaded with dust mite particles!
There
may be many as 19,000 dust mites in one gram of dust, but
usually between 100 to 500 mites live in each gram. (A gram
is about the weight of a paper clip.) Each mite produces
about 10-20 waste particles per day and lives for 30 days.
Egg-laying females can add 25-30 new mites to the population
during their lifetime.
Mites
eat particles of skin and dander, so they thrive in places
where there are people. Dust mites don't bite, cannot spread
diseases and usually do not live on people. They are harmful
only to people who become allergic to them. While usual
household insecticides have no effect on dust mites, there
are ways to reduce exposure to dust mites in the home.
Why
is mold present in house dust?
Mold is commonly found in outdoor air. However, any house
can develop a mold problem given the right conditions. You
might not see it growing on the walls, but it may still
be present in your home. Mold require two factors to grow
indoors: (1) free moisture that can occur in the form of
relative humidity above 50 percent, leakage from pipes or
foundations, or any ongoing source of water, and (2) something
to grow on. Molds particularly like to grow on wallboard,
wood, or fabrics, but will grow virtually any place if they
are given a chance.
Mold
spread by producing spores that can become airborne. These
spores end up in house dust where they grow. Dust from mold-contaminated
houses can cause allergy symptoms if a mold-sensitive person
inhales it.
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