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 however 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 encase pillow, mattress, and boxspring with 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 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 one 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 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. 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. 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 for individuals to track into the bedroom, but they are still allergenic. Similarly, short hair is somewhat better than long. 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 clean everything including the ceilings. It still takes several months after pet removal 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 (plus cockroach or mice 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 classroom 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 office worker some amount of pet allergen exposure. Depending upon the number of students / fellow workers who own pets, this exposure can be extreme. I have had to move the occasional child who was severely and primarily allergic to cats, to another class which 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 ( increases the severity of existing allergies and increases the risk of developing new allergy problems). 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, 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 non carpeted 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. Furniture (especially furniture upolstered with permeable material) can act as a major reservoir for pet allergen just like carpeting does. Ideally, furniture should be upolstered with non permeable material - leather and similar materials - so the furniture can be wiped down with a damp-magnetic cloth (these dust collecting cloths have a permanent magnetic charge and are very good) every time the room is vacuumed. If a pet sleeps/rests on permeable upolstery, this upolstery should be vacuumed every time the room is vacuumed and these pieces of furniture should be covered with a sheet (or similar covering) with the cover sheet being washed every week. It is absolutely necessary to have an appropriate vacuum that will pick up pet allergen and not reaerosolize these ultra fine particles (which go right through standard vacuums and are then discharged directly into the air) -either a central vacuum discharged to the outside (best) or a vacuum with a good 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 NilfiskTM, use only a vacuum recommended by your allergist, do not believe manufacturers claims. (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 only outdoors, where the allergy particles are blown away. Clothing that contacts the pet should never get in the allergic persons bedroom - until it has been washed. To summarize pet control: rinse pet every three days, remove carpets, restrict animal access, use an appropriate vacuum and vacuum daily, no licking or cuddling, encourage outdoor contact, and wash hands. If this cannot be done, the pet should be removed. My last comment is that once this pet has passed away, do not get another indoor pet. Outdoor pets are rarely a significant problem.

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, pollens are released by plants into the air during the daytime (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. Only plants that aeropollinate represent significant aeroallergens. Many plants are pollinated by insects, and these do not have a significant aeroallergy 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. Immunotherapy is a highly effective treatment for many pollen allergies.

MOLDS

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 center around the allergic potential of molds and related spores (we know that the spores from mushrooms (basidiomycetes), puffballs, etc. can also cause allergy). However, there is good evidence than 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 estimated to be over 1.5 million different members of fungi group/family. We know that several hundred 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 upon 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 will have a mold problem. Any house that has visible mold-mildew has an indoor mold problem. What most individuals don't realize is that under most conditions there are still mold spores in the outside air. Unless we have bitterly cold consistent winter weather (nights 30 deg.C below, days below 20 deg.C below) there are mold spores in the air. Particularly, when you get above temperatures of 10 deg.C below zero, 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 molds 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. So 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. You must also have clear cut positive skin tests to molds to diagnose mold allergy plus a history that fits with 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. 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 ".

So what can we do to avoid molds. Indoor molds can be controlled by frequent cleaning of any area suspect of having mold or mildew. 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 dose not control the mold growth you can try baking soda or bleach (never mix these) as specific molds can be killed/controlled with specific cleaning agents. Garbage cans and any moist area should be regularly and meticulously cleaned. 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 the mold (and dust mite and pet allergen). I am always amazed at the evidence of chronic mold growth in 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 inside 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 they kill mold spores, BUT, UV light is very harmful to the eyes and bleaches (takes color away). UV lights cannot be used where people 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 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, and put in a weeping tile system (plus or minus a sump pump depending on drainage conditions), with good gravel fill. A special mention should be made about eves troughs and downpipes. Every house should have good eves 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 can only be done with the patient clearly understanding its limitations, and when nothing else is helping.

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 carcinogenesis, etc. No individual with allergies should be exposed to ETS (nor should anyone who wishes to avoid 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). What is interesting, is that 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 are produced by using powerful petrochemical solvents to extract specific odors - often from specific flowers. These extracts are then mixed to produce a specific perfume. The majority of a perfume is composed of solvent. These solvents can act as severe chemical irritants. Should you doubt this, spray a perfume into the air and walk through the spray 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). Just like ETS, some individuals can actually be allergic to the plant component of perfume also. There are thousands of true irritants in the environment : all smokes (products of combustion), vehicle exhaust, cleaning agents and solvents, dust of any kind ( from road dust to chalk dust), fine particles (ie. fiberglass particles), etc. The list is endless.

The treatment of all irritant reactions is avoidance. We have no medication to block irritant reactions (like we have to block or modify true allergic reactions). If you are exposed to significant irritants, you should leave the area as quickly as possible. The list of irritant substances is long and you should strive for an irritant free house and workplace.