ALLERGENS
and AVOIDANCE
This section specifically deals with common
allergens and some of the routine avoidance measures required. This will continually be updated as
increasing knowledge and time permits. It
is not meant to be an exhaustive discussion but to point out common, practical,
or interesting aspects.
DUST MITE
The majority of individuals with allergy have
some degree of allergy to dust mite.
This allergen is everywhere (ubiquitous) in homes where there is
carpeting and bedding or permeable covered furnishings. There are two common species of dust mite in
temperate climates, and often an individual house will contain much more of one
species than the other. There exists
some cross reactivity between dust mite allergens with also unique allergens
for each individual species. Dust mites
feed primarily on shed human skin scales.
Humans constantly shed skin scales in amounts that you would find hard
to believe. They can survive on other foods, including
mold spores. They are found in
concentrated numbers and breed in areas with high skin scale concentrations. Usually, the highest concentration of dust mite is found
in the mattress. Mattresses contain huge
amounts of skin scales, sufficient to feed dust mites for years. The average mattress is totally infested with
dust mites within six to 12 months of purchase and subsequent use. An old mattress will contain millions of dust
mites. I always like to tell patients
that they would find it much easier to properly encase their mattress if they
could see the mites. Just remember, you
are sleeping on a seething bed of dust mites.
The majority of dust mite allergen comes from the fecal material-pellets
of the dust mite. These mites are just
below the ability of the human eye to see, approximately 0.3 mm. The fecal material is much smaller and when
disturbed by moving in bed, walking on carpets, etc. stays in the air for
approximately one to two hours. This
means the average individual sleeps in a cloud of dust mite particles all
night. Some dust mite allergen is much
smaller and can stay in the air for many hours.
Dead dust mite bodies fall apart and also provide some allergenic
material. See the picture of a dust mite
and note the 8 legs. These powerful legs
can hold onto fixed fibers in mattress, carpets, upholstery and there is
absolutely no way you can remove a dust mite that is holding onto a fixed
fiber. No vacuum in the world will pull
live dust mites off fixed fibers.
Vacuuming will remove dirt and dead dust mites. Unfortunately, standard vacuums will put out
all the allergenic particles at the canister end of the vacuum, as these
particles are too fine to be caught by standard vacuum filters. The only way you can eliminate mites from the
bedroom is to totally encase (completely encircle and seal) pillow, mattress,
and boxspring with proper dust mite proof encasements. In
the old days we only had plastic which was very hard to sleep on (noisy and
sweaty) but newer synthetic encasements are much superior. Many drug stores sell these. I would encourage you to talk to your local
allergist about the best encasements available, because there is considerable
variation in efficiency and costs. My
Dust / Mold Free Bedroom sheet (go back to Contents page) gives all the
instructions required for the bedroom and appropriate phone numbers for my
surrounding area. There can be no
carpets in the dust free bedroom - carpets contain dust mites, molds, and often
animal allergen. Studies have shown that you must
remove carpets and encase to eliminate dust mites from the bedroom. All bedding must be washed in hot water and
dried on high heat (ideally 150 degrees F) in the dryer. Only heat consistently kills mites, and the
tumbling action in the dryer promotes removal of dead mites. While freezing can kill mites, it is neither
practical nor as efficient. Putting
bedding out on the clothesline to dry is totally inadequate and totally
inappropriate if you have any outdoor aeroallergies
(which most allergy patients do). The
bedroom should be kept free of dust collectors and junk. Once the bedroom is dust free, it takes only
half an hour per week to keep it that way.
Long term, you want to remove carpeting in the hall outside the bedroom
and eventually remove carpeting from any area a dust mite-mold allergic patient
frequents. Dust mites do not breed in
dry conditions (reduced breeding under 50% relative
humidity, no breeding under 40%) and most molds do not sporulate
under similar dry conditions.
Dust mites drive the allergy system. They increase the severity of allergies and
the risk of developing further allergy problems. While it is not unusual for individuals
allergic to dust mites to complain of a plugged nose upon waking up in the
morning, what you must realize is that most individuals have no specific
symptoms due to dust mite allergy.
Because exposure to dust mite is ubiquitous and constant, most allergy
patients have zero symptoms upon dust mite exposure. Proof of allergy comes from skin testing. This is an important concept, that continuous
exposure to an allergen does not cause acute allergy symptoms, because this
applies not just to dust mite but also frequently to personal pets where
constant daily exposure occurs. Just because your pet causes
no discernible symptoms, does not mean you are not allergic to it.
The Dust-Mold Free Bedroom sheet should be
copied, thoroughly understood, and followed to the letter! The dust-mold free bedroom is the single most
important thing that allergy patients must do.
In the long term it can improve overall symptoms, reduce medication use,
and particularly in children can reduce their chances of developing other
allergy problems. The only other
intervention that can possibly modify the allergic future of an individual is
immunotherapy. Medications control
symptoms but do not have a significant effect on the long-term progression of
the immune system. I do not routinely
recommend HEPA filters in the bedroom for dust mite allergy alone. HEPA air filters must be of good quality and
I strongly recommend you ask your local allergist specifically about which HEPA
filters are appropriate. Many brands are
inadequate. A good rule of thumb, is
that the replacement filter should be very expensive (for small units $50+, for
large units much more) or it likely is not a good HEPA filter. I only routinely recommend HEPA air filters
for the bedroom if the patient has significant mold allergies or pet allergies
with a pet remaining in the house.
PETS
Most of this discussion will consider dogs and
cats. However, most comments made apply
to virtually all fur bearing animals.
The actual particles that people are allergic to arise primarily from
the animal’s saliva and dander. The term
dander refers to the skin products (i.e. skin scale, skin gland products) that
the animal sheds. A portion of these
allergy particles are deposited wherever the animal lies, and carpets and
occasionally furniture act as major sources of animal allergen. A smaller amount of allergen can come from
urine. Male cats produce more allergen
than females. Airborne particles come
from the fur of the animal or from walking on carpets and stirring up these
particles. The main source of dog
allergen is saliva as dogs salivate much more than cats. Dogs tend to concentrate allergen just under
the chin and on the front of the chest as this is where a large amount of
saliva is deposited (and this is where you have to rinse particularly
well). An animal licks its fur, the saliva dries on the fur, then breaks off the fur in
small particles into the air whenever the animal moves. These particles are incredibly small and can
stay in the air for up to 24 hours. Any
forced air ventilation system will circulate these particles. Putting your pet in the basement is useless
if your cold air return for the furnace is pulling in animal allergen
constantly. If you touch the fur of an
animal, you bring away thousands of allergic particles on your hand. There is no such a thing as a non-allergenic
animal. Some animals with hair that
doesn't shed are somewhat better, because they do not leave shed hair scattered
throughout the house and for individuals to track into the bedroom, but they
are still allergenic. Similarly, a
smaller pet and shorter hair/fur is somewhat better. Allergy to animals is usually worse in the
winter in our climate as the house is closed for the winter with the heating
system on to efficiently circulate aeroallergen.
If you are allergic to your pet ( i.e. have
positive skin test to cat and own a cat) by far the best solution is to remove
the pet from the house and remove what carpeting you can and wash everything
including the ceilings, walls, floors, windows, curtains, etc with warm water
and a very mild detergent. It still
takes several months to have a complete reduction in allergen level. Remember, continuing to expose yourself daily
to major amounts of animal allergen that you are allergic to, often does not
cause acute allergy symptoms, and will drive your allergy system and increase
the chance of increasingly severe allergy symptoms and further allergy related
problems. In children pets are second
only to dust mites (occasionally cockroach in the inner cities) as the
initiating cause of asthma, and once asthma develops it is a permanent
condition in the vast majority of individuals.
Interestingly, there is evidence that in adult human males, cats are
number one in causing asthma followed by dust mites.
You should also be aware of how ubiquitous
cat-dog allergen is. Several studies
have shown that every single class room tested gave evidence of significant
detectable cat allergen. Any student can
expect to get some pet allergen exposure at school. Similarly, most large offices will give every
worker there some amount of pet allergen exposure. Depending upon the number of students /
fellow workers who own pets, this exposure can be occasionally extreme. I have had to move the occasional child, who
was severely and primarily allergic to cats, to another class that had a much
lower number of classmates owning cats. These
children did beautifully in the summer, until the first day of school. Studies have shown that 50% of houses that
have never had a cat as an occupant, have detectable
levels of cat allergen. Cat owners tend
to be covered in cat hair-fur, and wherever they go and sit they leave
significant amounts of hair and allergen.
Practically speaking, many pet owners refuse
to find another home for their pet. I
think it's very important that these individuals / parents understand the risks
involved in keeping their pet. On the
other hand, these animals are often a major part of a family and in some cases
the only companions that the allergic patient has. So what are we to do about this
situation? If the patient or parents
clearly understand the increased risks of keeping a pet, but decide to do so,
it is my job to reduce this risk to the lowest possible level. This concept I call pet control. What follows is not negotiable, and I clearly
state that all these measures must be done without exception. The vast majority of the allergy particles on
the fur are water soluble. If an animal
is given a thorough 3 minute rinse with lukewarm water (lukewarm to avoid
frightening the animal, but I don't guarantee they'll like it) and then dried
with a towel, at that moment the animal is virtually non-allergenic. It takes approximately 4 to 5 days for most
animals to accumulate a full load of allergen back on their fur (needless to
say, this is variable). If the animal is
rinsed every three days (2 days for those where animal allergy is the primary
allergen), you drastically reduce the amount of allergen getting into the
air. You must not use shampoo or soap on
the animal, as this dries out their skin and results in increased dander
production and a more allergenic animal - lukewarm
water only every three days. All carpets
must be removed from the allergy patient’s bedroom immediately, and removal of
all carpeting in the house should occur within six months. It's preferable to keep the animal in
specified rooms of the house, and these must be vacuumed daily to pick up
animal fur and prevent the tracking of this fur to other rooms, particularly
the bedroom. It is necessary to have an
appropriate vacuum-either central vacuum discharged to the outside (best) or a
vacuum with a HEPA filter that has been scientifically studied and shown to be
effective. Note :
many vacuum manufacturers claim to have HEPA filters, most have not been
adequately studied. I recommend a vacuum
that states it uses a “true HEPA filter”, do not believe manufacturers claims
if this is not stated. (The same applies
to HEPA air filters for bedrooms). If
the allergic individual touches the pet, they should immediately wash their
hands with soap and water, making sure they do not touch their face (parents
must teach children to do this). Never
allow the pet to lick the face or sit in the lap. I strongly recommend the allergic individual
contact the animal outdoors, where the allergy particles are blown away. To summarize pet control : rinse every three
days, remove carpets, restrict animal
access, use appropriate allergy vacuum daily, no licking or cuddling, encourage
outdoor contact, wash hands and any licked areas. If this cannot be done, the pet should be
removed. My last comment; once this pet
has passed away, do not get another pet.
POLLENS
I will spend little time on pollens. Each geographic location has its specific
pollens at specific times and any good local allergist will know these
well. Pollens are clearly seasonal and
occur at roughly the same time of year, depending upon the specific weather
pattern that year and the specific trigger for pollination (for example,
temperature, length of day, humidity).
In general, the majority of pollen is released by plants into the air
during the daytime (while you will still have some pollen in the air at night,
only if it is very windy will you get significant pollen in the air at night),
and pollination increases during dry sunny weather and is usually maximal in
the early afternoon. Heavy rainfall will
often clear the air of pollen for a few short hours. If your symptoms do not clear at all immediately
after heavy rainfall, it suggests that molds are primarily driving your
allergies – not pollens. Paradoxically,
light rain or isolated thunderstorms can cause pollen particles to burst,
becoming much smaller than the original whole pollen particle.
These small burst particles can enter the lower airway and induce an
acute asthma attack in pollen allergic individuals. This
“thunderstorm asthma” can occur in pollen allergic asthmatics but can also
occur in pollen allergic patients who have never had an asthma attack and do
not have persistent asthma. Only plants that aeropollinate represent significant aeroallergens. Many plants are pollinated by insects, and do
not present a significant aeroallergen potential. Many patients think they are allergic to these
insect pollinated plants because they see these plants flowering at a time when
their allergies are worse. In my region
many people think they are allergic to dandelion or goldenrod (both insect
pollinated). Most plants that have
colorful flowers are insect pollinated as the flowers attract the insects. Most airborne pollinators have inconspicuous
flowers (ragweed, mugwort, etc.).
Immunotherapy is a highly effective treatment for many pollen allergies
if basic allergy medications are not successful in controlling seasonal
symptoms.
MOLDS (MOULDS)
Molds are members of the larger group of
fungi. They produce small reproductive
particles called spores. We know that
mold spores can be highly allergenic. We
also know small fragments of the body of the mold structure can also be
allergenic. In addition to producing allergic
reactions, molds and fungi can cause a variety of direct toxic effects in
humans and some can also cause infection (i.e. the yeast Candida
Albicans). My discussion
will concentrate on the allergic potential of molds and related spores (we know
that the spores from mushrooms, puffballs, etc. can also cause allergy). However, there is good evidence that molds
are changing in response to pollution, and some of the effects we see from
molds may be due to increased toxicity also.
There are over 1.5 million different members of the fungi group. We know that several thousand commonly
produce airborne spores. We commercially
produce testing and treatment material for several dozen molds only. You begin to see the problem. It is such a huge family that studying these
spores from an allergy viewpoint has been extremely difficult. Moreover, these spores tend to change
depending on specific growing conditions, and even identification can be a
problem. Whereas pollens travel up to
several hundred miles in windy ideal conditions, mold spores can travel
thousands of miles and are found high up in the atmosphere. The individual members vary hugely in their
characteristics, what they feed on, conditions for sporulation,
etc. While some molds produce spores
during dry conditions, most tend to selectively release spores when humidity is
increasing, damp weather, or during the evening-night where the air is cooler
and more humid. Common molds can live
happily inside homes and in the outside environment. Any house that has been flooded or has
excessive humidity will have a mold problem.
Any house that has visible mold-mildew has an indoor mold problem. What most individuals don't realize is under
most conditions there are still mold spores in the outside air. Unless we have bitterly cold consistent
winter weather (nights -30 deg.C, days below -20 deg.C) there are mold
spores in the air. Particularly, when
you get above temperatures of -10 deg.C,
these cold weather mold spores and fragments come off the coniferous trees in
our area. When the late winter
approaches and temperatures rise to 0 there is significant mold coming off all
trees in our area. Once the snow melts
and the ground is exposed, there is a major increase in ground mold spores from
then until full winter sets in again. The
main point to be made is that outdoor molds are always around, but increase
during damp and night conditions. Mold allergy can
affect the nose, sinuses, and chest.
While mold spores can produce any of the classical allergy symptoms we
have covered already, there are some unique aspects. Mold allergy, more than other inhalant
allergies, is associated with fatigue, and often quite severe fatigue. A major word of caution here, the fatigue
must be fluctuant in nature, and the changes in fatigue must be associated with
other allergy symptoms. Constant,
unremitting fatigue is not caused by mold allergy and you would look at
diseases such as thyroid, diabetes, depression, or chronic inflammatory
diseases like severe arthritis, or cancer.
It is desirable have clear-cut positive skin tests to molds to diagnose
mold allergy. However, having said this,
I find that many persons who are allergy tested are totally inadequately tested
for mold allergy. Molds are a special
interest of mine, and if you have been tested properly for mold allergy, you
should have received at least a dozen specific skin tests for specific molds to
determine if mold allergy exists. There
are countless thousands of allergenic molds we do not have test material for. Many allergists do not test adequately for
molds. (On a similar note, a
considerable amount of skin testing is inadequate in both the number and scope
of tests done). The other rather unique
aspect of clinical mold allergy is when the allergy is significant, many mold
allergic individuals feel genuinely ill, unwell, like the "flu". If you have significant allergy to molds your
symptoms should often (not always, but often) worsen with weather changes and
the time that you feel your very best (fewer allergy symptoms & more
energy) is during a long very cold snap in the winter (several sunny-clear days
around -30 degrees).
So what can we do to avoid mold? Indoor molds can be controlled by frequent cleaning
of any area suspect of harboring mold or mildew. Mold damaged materials such as carpeting,
insulation, drywall, and wood must be removed.
Even a small spot of visible mold can produce a large number of spores
(the question is, are you allergic to that specific mold/spore?). Any commercial cleaning agent is reasonable,
as long as it does not bother you, and adding vinegar to it can help. If this does not control mold growth you can
try bleach, which will kill all molds it contacts, but you must wear proper
skin protection and have the area well ventilated. Garbage cans and any moist area should be
regularly and meticulously cleaned, preferably with bleach. Ideally there should be no carpeting. Certainly there must be no carpet in any area that gets
repeatedly wet/damp. Carpets are a huge
source of molds. Every time you spill
liquid on a carpet or steam (wet) clean a carpet you increase the mold content.
The older the carpet, the more mold it
will contain (plus dust mite and pet allergen). I am always amazed at the evidence of chronic
mold growth on the underside of carpets (or underlay) that have been removed
from dwellings - even carpet from areas that were felt to be scrupulously dry. Carpets in basements are guaranteed to have
significant molds. The most important
aspect of controlling indoor mold is to keep the humidity in the house
down. Ideally, below
40% relative humidity. A
humidistat (hygrometer) is useful, but it only reflects the relative humidity
of the area that it is placed in. Molds
tend not to sporulate in low humidity. I often recommend a dehumidifier in the
basement, with the water collection tray having a permanent drain hose into a
covered floor drain (so the water collected continuously is removed) and the
unit left permanently plugged in. During
the winter in our climate it often will be idle, but from spring through fall
usually runs steadily. The use of humidifiers is to be
strictly avoided in mold allergic individuals, as the increase in humidity
increases general spore production in the house and virtually all humidifiers
grow molds themselves. This is
particularly true for central humidifiers which are often impossible to clean
properly. I recommend all humidifiers be
removed from the house. Any area that sees significant
moisture accumulation should have a good exhaust fan and this should be used
every time the area gets an increase in humidity (i.e. during and after a
shower, after a sauna, etc.). Always
regularly clean the defrost tray in the bottom of the fridge (a very common
mold source) and the collection tray in any air conditioning unit. Never use a live Christmas tree - as soon as
the tree starts to thaw out, mold spores are released off the bark and needles. Many people who have noticed this situation and learned to
avoid real indoor Xmas trees incorrectly assume they are allergic to the tree
itself (although I do have a few patients who are allergic to the tree needles
or sap, these are primarily individuals who work with wood - carpenters, lumber
or pulp&paper company employees). All mold allergic people should use artificial
Xmas trees. If your windows collect a
lot of condensed water on the inside during cold winter weather, applying a
layer of plastic to the inside of the window (including the frame) can be very
useful in preventing the condensation build up. These plastic coverings are readily available
from most hardware and general stores in the fall. For windows that get severe condensation, use
the plastic covering inside and outside. Note: these coverings must be applied in the
late fall on a warm dry day when the window is completely dry, so no
significant moisture is sealed between the plastic cover and the window. If you have visible mold growing in an area
(esp. basement) that frequent cleaning does not control, you can prevent this
by shining a standard spotlight on that area continuously. The heat and radiation from the spotlight keep
the spot dry and reduces sporulation. An ultraviolet (UV) light is ideal, as it
kills molds and their spores, BUT, UV light is very harmful to the eyes and
bleaches (takes color away). UV lights
cannot be used where people or pets might accidentally look at the UV light
(it’s a pretty blue color), or if there is any possibility of children
accessing the area. However, for an area
such as a crawl space or dugout basement with a major mold problem, an UV light
can be useful, IF the area is totally inaccessible. A safe and practical solution for basements
that have a permanent dampness/mold problem is as follows: install a small fan
in a basement window or opening in a basement wall, the fan runs continuously
discharging air from the basement to the outside, this way air always flows
from the house above into the basement and then outside (preventing mold spores
from getting into the house above and drying out the basement air through
constant air changes). The best way to
prevent a damp basement is to dig all around the outside foundation, put in a
weeping tile system (plus or minus a sump pump depending on drainage
conditions), and cover with good gravel backfill. A
special mention should be made about eve troughs and downpipes. Every house should have good eve troughs that can handle
all rain situations and the spring melt. The downpipes must discharge to areas well away from the side
of the house where there is good natural drainage away from the house (4 inch
flexible drainpiping does an excellent job). Proper downpipe
discharge is easy to accomplish, a frequently overlooked situation, and is an
absolute must to obtain a dry basement. Outdoor molds
cannot be completely avoided - you have to breathe. However, individuals who are mold allergic
must have a complete dust-mold free bedroom (no carpets, full encasements) and
the bedroom window should always be closed, and a HEPA air filter in the
bedroom is recommended. The ideal is
central air with full HEPA filtration, as central air conditioning keeps the
humidity in the house down regularly, (but in our colder climate this is often
impractical). Although, allergy shots
(immunotherapy) can be useful for severe mold allergy, the question always
remains, are there other molds that the individual is allergic to that we
cannot test for? Immunotherapy for molds
should only be done with the patient clearly understanding its limitations, and
when symptoms are not controlled with avoidance measures and medications.
MICE
Allergy to mouse allergen is very common. Up to 40% of houses have detectable levels of
mouse allergen, with many of the owners claiming they have never had mice in
the house. Mice themselves are
allergenic, but mouse droppings and urine contain significant amounts of
allergen. Most individuals know how
mouse droppings can be scattered over an area, but they are unaware that mice
constantly urinate on surfaces also (you cannot see this except under oblique
light on a very smooth surface such as glass).
Anyone with allergies should ensure that any mice are eliminated from
their dwelling. Any area contaminated
with mouse droppings should be initially cleaned with water and mild detergent,
and then this area should be wiped with a dilute bleach solution (1 part bleach
to 9 parts water) to completely denature the allergen (render it chemically
inactive as an allergen). Wear gloves
and ensure good ventilation so you do not inhale the chlorine fumes.
IRRITANTS
While virtually any dust, powder or odor
can act as an irritant to an individual with allergies (remember, the allergic
inflammation of the respiratory lining makes it much more susceptible to
irritant stimulation) no discussion of avoidance measures would be complete
without covering tobacco smoke (ETS) and perfumes.
Tobacco smoke is composed of over 4000
different chemicals. These chemicals
arise from the combustion of the cigarette.
Remembering, that up to 40 percent of a cigarette is not tobacco
-additives, chemicals added to enhance
nicotine uptake, insecticides-pesticides, fertilizers, paper (many toxic
chlorine products), the filter - we know that many of these chemicals cause
severe chemical irritation or chemical
inflammation. In allergic individuals
this chemical irritation occurs on top of the already present allergic
inflammation. Exposure to ETS doubles an
allergic child's chance of developing asthma.
Any individual with respiratory allergies will be made worse with
exposure to second hand smoke. This does
not even address the issue of carcinogenisis,
etc. No individual with allergies should
be exposed to ETS. Family members who smoke, must smoke outside, never inside,
regardless of weather conditions, etc.
Also, it's critical that exposure to ETS not occur in enclosed spaces
(particularly vehicles where the concentration of ETS can be several times that
of indoor smoke!). You can also be truly
allergic to tobacco, thus it can represent a double-edged sword, acting as an
allergen and irritant.
There is considerable similarly with
perfumes. Perfumes used to be produced
by using powerful petrochemical solvents to extract specific odors - often from
specific flowers. These extracts are
then mixed to produce a specific perfume.
Many modern perfumes are made up of various petrochemical molecules that
have been manipulated and mixed to produce specific smells. The majority of a perfume is composed of
solvent. These solvents can act as
severe chemical irritants. If you ever
walk through a perfume/cologne spray cloud with your eyes open, when one of the
perfume droplets hits the eye, it's like a hot poker in the eye. This is the solvent irritating the normal
lining of the eye (not the already inflammed lining
of the allergic individual). Perfumes
are highly flammable! Just like ETS,
some individuals can actually be allergic to the plant component of perfume or
to a specific molecule within a perfume mixture. Individuals who have experienced one or more
reactions to perfumes often develop a psychological aversion reaction to all
strong odors. These psychological
reactions can cause significant physical symptoms; similar to the symptoms seen
in a panic attack/phobic reaction, or triggering off an asthma attack (strong
emotion can trigger asthma in some asthmatics). True
allergic reactions will consistently occur with exposure only to specific
perfumes, not to all perfumes/smells.
Most reactions to perfumes/colognes/petrochemicals/cleaning agents/etc.
are irritant reactions.
Pollutants make up a large and
ever-increasing source of irritation for the allergic and non-allergic individual. Many of these products of western
civilization and industrialization are truly a global phenomenon. Many airborne pollutants such as nitrous
oxide, carbon dioxide, sulfur dioxide, ozone, and so on, are dispersed through
the atmosphere of our planet and every living organism is exposed to the
increasing concentration of these products.
The carbon dioxide level in our atmosphere is now higher than at any
other measurable time in our planet's recent history. Molds have been shown to be put under
increased stress with increasing carbon dioxide concentrations and produce more
spores (and possibly more mycotoxins) under these
conditions. Increasing concentration of
all of these airborne pollutants has been shown to increase hospitalization and
healthcare usage of individuals who have significant respiratory disease (COPD,
asthma, etc.). These individuals are
routinely told to stay inside when there are particularly high levels of
airborne pollutants-smog. It is
worthwhile wondering what the effect on every individual is when exposed to
these increased levels of airborne pollutants on a continuous basis over many
years. While most people have heard
about the ozone layer that is being depleted in our upper atmosphere, many do
not realize that ground-level ozone has increased due to pollution. Ozone has been clearly shown to be a
respiratory irritant. Particular mention
should be made of air cleaners that have ionizers. All these units will produce ozone and should
not be used in enclosed spaces in an attempt to clean the air (particularly in
an enclosed bedroom and so on). Air
cleaners that have HEPA filters are excellent, but make sure they do not have
an ionizing component. One of the major
components of air pollution is particulate air matter. These particles are extremely complex and
arise as products of combustion (soot, carbon particles, etc.), from mechanical
sources (small rubber particles from tires on highways), and from a large
variety of other sources. Some of these
particles can be increased markedly under local conditions (such as living
right beside a large high speed Highway) or with the right weather conditions
(such as lack of wind and inversion conditions causing severe smog). Many of these smaller particles are widely
distributed in the atmosphere. These
particles are usually described according to their size. PM 10 describes particles that are under 10u
(microns) and PM 2.5 describes particles that are under 2.5u. PM 10 particles usually land only in the
upper respiratory tree (nose), whereas PM 2.5 particles are small enough to
easily enter the lower airway and deposit in the smaller tubes in the lungs. Diesel exhaust particles have been shown to
adversely affect individuals with allergies in multiple ways. Diesel exhaust particles can directly
stimulate the allergic inflammation in the respiratory lining and have also
been shown to have the ability to combine with allergenic particles (pollens,
pet allergen, etc.) and the resulting combination particle induces more severe
allergic inflammation than the original allergen (without the diesel exhaust
particle attached). With the increased
trucking in all industrialized countries these particles are steadily
increasing worldwide and there is no likelihood this increase is going to slow
down in the next few decades. There has
been an increase in indoor irritants-pollutants. Energy efficient buildings have increased the
airborne concentration of many substances ranging through thousands of
compounds that come from carpets-adhesives-paints-etc. off-gassing, poor
ventilation systems, inadequate cleaning, various cleaning agents, water-mold
damage - the list is disturbingly long.
Over the last 20 years allergic diseases
have increased in frequency and severity in both young and adult
populations. While the causation of this
is multifactorial and environmentally based, I am
convinced that the increase in exposure to irritants and pollutants is one of
the driving forces behind this. I
routinely see both adults and children who can acutely worsen over a period of
days or gradually worsen over a more extended period of time where there is no
discernible evidence of increased exposure to true allergens. Many times I am suspicious that it is
increased exposure to irritants and pollutants that is driving the allergy
system and making symptoms worse. This
is a rather frightening scenario as there is no evidence that the human race is
making any significant-meaningful effort to curb the increase in pollutants.
The treatment of all irritant reactions is
avoidance wherever possible. We have no
medication to block irritant reactions (like we have to block true allergic
reactions). If you are exposed to
significant local irritants, you should leave the area as quickly as is practical. The list of irritant substances is long and
you should constantly strive for an irritant free/reduced home and workplace. There is a rapidly increasing group of
individuals in our society who do not have any evidence of an ability to have
true allergies, who have negative skin testing to a large number of know
allergens, yet have a reaction (direct irritant or irritant induced
inflammation) in the respiratory lining of the nose and sinuses that is caused
solely by exposure to the irritants and pollutants discussed above. Some individuals are much more sensitive than
others to irritants. While non-specific
medications such as nasal anti-inflammatories and decongestants can be helpful
in some of these people, specific anti-allergy medications (antihistamines,
etc.) will not help, as this process does not have an underlying allergy basis.
Dr.
Bruce Sweet 2010