Strangers among us
It’s a face only a mother could love. Strictly speaking, of course, a house dust mite doesn’t really have a face, as we understand faces. Nor, for that matter, does it have eyes with which to see such a thing, were it ever to come face to face, so to speak, with another mite – which, one suspects, happens fairly often. That’s because dust mites, which thrive in the moisture and dust in carpets, fabrics and especially bedding, are rarely in short supply in the average home. When you roll out of bed in the morning, you leave about two million of the little beggars in your mattress, pillow and bedding, pining for your return – probably twice that number if you’re half of a sexually active couple.
Dust mites are members of the arachnid family, distantly related to ticks and spiders. They’re a very special breed – dermatophagoides (literally, skin eaters) – that survive on the gram of scaly particles each of us sheds every day. A mere 300 microns in length (.3mm), dust mites remain invisible to the naked eye as they go about their brief lives (10 weeks from egg to end), absorbing and shedding water through their skins, each leaving behind about 20 minute droppings per day.
. Jill Warner, a lecturer in child health at Southamptom University Hospital, noted in a British magazine that it wasn’t until the 1960s “that it became appreciated that the major factor in dust that people were allergic to was the dust mite. Studies world-wide have now shown that up to 85 per cent of people with allergic asthma are sensitive to mites and that this allergy is an important contributor to the development and severity of their symptoms.”
Furthermore, “studies have identified that it is a protein in the faecal particles, or droppings, of the mite, termed Der p1, to which patients with allergic tendencies become most sensitized. This is because these are very small particles, about five microns in size, and become airborne when dust is disturbed and thus easily breathed in.”
How to combat such a tiny foe? Most of us don’t need to; we and the mite cohabit with perfect equanimity. But, if you’re sensitized to its presence, there are a good number of strategies you can employ. The first step is to confirm, with the help of your allergist or other healthcare professional, that it is indeed dust and the mite to which you’re allergic.
“Basically what you want to do is clean your environment of those things you’re allergic to,” says Lisa Cicutto, Ph.D., a nurse practitioner, and an asthma educator with the Michener Institute at the University of Toronto. “If you don’t have a problem with allergies, I’m not going to nag you about [changing] your pillow. We really only counsel individuals to do those behaviour changes or to control their environment if it’s an issue for their health.”
While Cicutto and her colleagues don’t actually visit their clients’ homes, they do use an extensive questionnaire to get a sense of what the client’s home environment is really like, and they spend time talking with the client, trying to fill in the picture. Is the client living in a basement apartment, do they have a humidifier, dehumidifier or air conditioner? A wood-burning or gas stove? How about a fireplace? Do they have all wooden furniture, or do they have old, upholstered pieces? Might it have horsehair in it? Are there carpets? Books? Stuffed animals? Once they’ve narrowed the field, Cicutto will often test for allergens using “the skin-prick method” – what June Engel, in The Complete Allergy Book, calls “the cheapest, safest, simplest and most commonly performed test for an allergy.” It only takes a few minutes and gives “a good index of allergic response. A few drops of specially prepared common allergen extracts are introduced beneath the skin on the forearm or back, and the skin sites are examined after 15 minutes to see if there’s any Ôweal and flare,’ indicating sensitivity to any of the allergens.” It’s not foolproof, but it can give a pretty good indication if you’re allergic to some of the common allergens, Cicutto says, “such as moulds, house dust and house dust mites – because for some people house dust is more of an irritant. House dust actually contains a lot of different stuff. You can be in a very dusty environment, or it can just be dirty.”
Single-pane windows, for instance, can allow a lot of traffic dirt and city smog to get into a house or apartment, and there’s a fair amount of mixed particles that drop off our clothes, as well as food particles, flakes of skin and so on. “People have different thresholds of response to dust,” Cicutto notes, “but you’re never going to achieve a dust-free environment. We don’t want people to live in bubbles.”
The idea is to narrow down the search, be selective about what you eliminate from or tone down in your environment (there’s no sense taking extraordinary measures if they’re unnecessary). “We usually recommend concentrating in the bedroom,” Cicutto says, “because it’s where we spend a significant portion of our day in one place. Most of us sleep anywhere from six to nine hours. You’re shedding flakes of skin everywhere you go, but you usually aren’t in one place for such a long period of time. And most places you don’t have much control over, but you can have a fair amount of control over your bedroom.”
Cicutto works from the bottom up. Carpeting, an ideal refuge for mites, is not advised. If you must have a rug, make it low-pile synthetic, something you can vacuum and shampoo regularly. Hardwood flooring would be better, linoleum better still. “And now they have linoleum that looks like hardwood floors,” Cicutto says. “It’s even easier to take care of than hardwood. And cheaper.” But, she says, “if you’re not sensitized to house dust mites, I’m not going to say get rid of your carpets – unless there’s something else in the carpet you’re sensitized to. Sometimes there are adhesives and things that act as irritants to airways.”
Ideally, walls and ceilings should offer mould and dust as little opportunity to get a grip as possible; keep surfaces as smooth and as easy to clean as you can. (If you’re repainting, consider adding mould inhibitor to the paint before applying.) Go for simple, scrubbable window shades (not venetians). “You don’t want any of those balloon things or big valances,” Cicutto advises. “And you don’t want big stuffed chairs in your room. If you’re going to have a chair, make it wooden, plastic or steel. You don’t want huge bookcases with all your novels, either. If you’re a kid, don’t be showing off your 50 stuffed animals. Barren, really, is what you’re going for in your room.”
If “barren” sounds bleak, remember that we’re just talking about your bedroom; you don’t have to turn your entire house or apartment into a hospital ward. Before we leave the bedchamber, though, there’s the little matter of bedding.
Again, start at the bottom: Encase your mattress and box spring in allergen-impermeable zippered covers. Thick plastic sheeting will do, but you’ll find it makes a racket every time you roll over in bed. In fact, there are several grades of impermeable material available through home-health companies, from basic plastic to more expensive covers with a cloth-like or linen feel, all of them providing a vapour barrier that prevents mites from enjoying your heat, moisture and dead skin.
“We also recommend encasing pillows, because you’re lying there with your face on the pillow for hours,” Cicutto says. “A lot of people have a pillow they hang on to for a long time, because it’s comfortable – it becomes like a buddy. But, after about a decade, half the weight of that pillow is not pillow. As you approach 10 years, half the weight of your pillow is house dust mites, living and dead. Feather pillows tend to accumulate even more dust, and they have a lot of antigen all of their own. The same with down duvets.”
In sheets, blankets, duvets and other bedding, synthetic is better, Cicutto says. “We don’t make a big deal about it. If you want to go to synthetic sheets, go ahead, but most people find they’re quite staticky and not as comfortable. So, a blend. The big thing is that you wash them, at the very least every two weeks, preferably once a week – and in hot water, because hot water denatures the mite protein, which is what you’re allergic to. It kills the mites as well.” Unfortunately, most North American washing machines won’t kill all the mites. They simply aren’t hot enough. You only need about five minutes at 60 degrees C. (140F) to do the job, but by the time hot water gets from your water heater, through the pipes and into the cold drum of your machine, “you’re probably looking at close to 40, 45 degrees,” says Carolyn Cross, marketing coordinator for Miele and Co., a European home appliance company. “So, you’re not starting with hot water, but even if you did, in less than a minute the water temperature would be lower than what you started with.”
The solution is a Miele machine, or one of its European competitors: All come with built-in water heaters, which ensure that the water starts hot and stays hot. They use about half as much water as the average top-loading North American machine, Cross says, “but they wash about the same size load. You could do a queen-sized duvet. Our machine also uses about a third of the energy of a standard North American machine, because you’re using so much less water.”
Of course, you pay for all that capable piping – anywhere from $2,000 to $2,600. Cross estimates the average user will make the extra expense back in Hydro savings, but that’s not why people buy them: “Most people buy one because it cleans better and cleans more gently,” she says. “It’s a more effective machine.”
The other big anti-dust mite machine, of course, is your vacuum cleaner, which may or may not be doing everything you think. It does no good to vacuum twice a day, for example, if you never empty the bag, Cicutto points out. “All you’re doing is spewing more of the dust and dirt into your environment. Instead of letting it settle, you’re churning it up.”
In addition to changing the bag, Cicutto suggests letting someone else do the vacuuming, while you – or whoever’s allergic to dust – go for groceries. Before you get home, the dust has had a chance to settle and there aren’t so many particles floating around in the air.
Again, it’s a question of technology. Buy a European vacuum cleaner and you’ll get a machine that filters the exhaust air, which most (but not all) North American machines don’t (though a HEPA filter’s essential; anything less isn’t fine enough to comb out allergenic particles). What you get for your money ($500 to $1000) is a quality machine with good suction and good airflow. “Very rarely do you find both,” says Carolyn Cross. “You’ll find that in a Miele. And you have a completely sealed system, which enables it to retain particles within the vacuum, rather than expelling it in the exhaust air.”
(If you can’t replace your vacuum with a high-end model, try wearing a filter. Soft, contoured face masks with high-quality, replaceable filters can be worn comfortably for hours. They have a variety of uses, from vacuuming to yard work to general clean-up and even sports, but make sure whatever mask you choose fits well to avoid an inadequate seal.)
The difference between vacuums is a bit like the difference between homes with radiators, and homes with forced-air heating systems, which move the air – and dust particles – around inside a house. Most of us turn the heat off in summer, Cicutto notes, “and we get all this settling and accumulation of dust in the air ducts.” Then, when the heat goes on again in the fall, all that dust is forced out into your environment, so get the ducts cleaned before you crank up the furnace. The other thing we recommend, Cicutto says, “is that when you first go to turn on the furnace, have a damp cheesecloth or something like that over the vents.”
There’s a wide range of commercial filters available for heating vents, in disposable and reusable, washable, forms. Some people go all the way with bedroom vents, not only preventing dust clouds from rising on forced air, but reducing the room temperature during the winter months, which makes the environment that much less inviting for mites.
There are any number of air purifiers available for home use, though Cicutto doesn’t generally recommend them, “unless you can afford one of the very, very expensive systems. They’re usually over $5,000.” That said, a less expensive, though good-quality machine with a HEPA (high efficiency particulate air) filter may be of help to some people in smaller, well-contained areas, such as a bedroom.
Masks and air filters can also be effective against other airborne allergens, such as moulds – microscopic fungi that live on plant or animal matter, which they decompose for their nourishment. Many of them reproduce by releasing spores into the air, where they’re easily inhaled, producing allergic symptoms. Moulds are found wherever there’s warmth and humidity, outdoors in piles of decaying leaves or other vegetation – and logs: If you have a fireplace, store firewood outside.
Inside, mould creeps into showers, laundry hampers, the corners of aluminum window frames (watch for condensation buildup) and damp basements. “If mould is a significant trigger for someone, a damp basement apartment can play havoc,” Cicutto says. “Dehumidifiers can help, but only to a certain degree.”
Air conditioners, which also extract moisture from the air, are often more effective than dehumidifiers, but they’re a seasonal solution, and their filters have to be cleaned or changed regularly. Year ’round, prevent over-humidification by keeping showers short and venting steam to the outside. Vent your clothes dryer while you’re at it, and send cooking vapours packing with a range hood and exhaust fan.
Bathrooms are especially fertile territory for mould. Be prepared to clean your shower curtain, tub and stall, toilet tank and tiles regularly with mould-killing and -preventing agents, and try to do without a bathroom carpet.
On the other hand, if your environment’s so dry you have to keep a humidifier humming – and you’re mould-sensitive – make sure your machine and filters positively squeak; moulds build up rapidly, and if the machine and filters aren’t clean, they’ll actually add mould to your environment.
The key message for people with allergies, Cicutto says, is that it’s important “to identify what you think is setting you off, what you respond to in your environment. You have to become a Sherlock Holmes, pay attention to details. Then go back to whoever it is you work with – your physician, nurse practitioner, whoever you see – and explore that with them. Help them to test whether or not you’re truly sensitized, or allergic, to it.
“It’s not fun or enjoyable to control your environment to such a degree. It can add a lot of burden to your life, so I don’t want people going out and becoming control freaks about their environment, if it’s really not a problem. You need to identify the issues, the important triggers for you, then decide how to go about reducing them to an acceptable level.
“It’s a balance of trade-offs, and not everyone has the money to do everything – or the willpower. Some people would rather take the medication and forget about cleaning their house or sleep with a down duvet. It’s about choices. It’s about getting as much information as you can that’s pertinent to you, and then working with someone to figure out your best strategy, given your preferences.”