When you know that dust mites are among the causes of your child’s allergic symptoms, you may want to reach for the vacuum cleaner every time you spy a trace of dust on the furniture. But vacuuming may not be the solution. Use of a normally efficient vacuum cleaner stirs up clouds of fine dust that can hang about in the air for up to 8 hours and make sneezing, runny nose, and itchiness worse. It’s best to wait until your allergic child is out of the house—at school for the day, for example—before vacuuming. Or to avoid stirring up dust, invest in a vacuum cleaner with a high-efficiency particulate air (HEPA) filter. To keep household dust levels down, clean all non-carpeted floors at least once a week with a damp mop and use a damp cloth to wipe flat surfaces, louver blinds, window ledges, and picture frames.
Air-conditioning and keeping doors and windows closed are effective ways to keep your home free of allergens and irritants brought in by air from the outside. While it may be too costly to install air-conditioning throughout your home, you may find an economical way to install a unit in your allergic child’s bedroom. This could help him sleep better at night and provide a low-allergen retreat on days when the pollen count is high. Air-conditioner filters should be checked and cleaned regularly, and sprayed with an anti-mildew aerosol to control the growth of molds.
Families may find their allergic members have fewer symptoms when room air is filtered through a HEPA air cleaner. However, air filtration should complement, not replace, measures to control mites. In fact, air cleaners do not significantly reduce mite exposure and should not be recommended for dust mite control. A HEPA air cleaner can be installed centrally in a forced-air ventilation system, or used as a portable room unit and left on at night in your child’s bedroom (see below). When you run a room HEPA cleaning unit, make sure the windows of the room are shut and the bedroom door is closed.
Dust Mites to Dust
Dust mites are the main source of allergens in house dust. It’s difficult for many people who are allergic to accept that these creatures, invisible except under a microscope, can be present in large numbers even in a thoroughly cleaned home. Some are convinced only when symptoms improve as a result of mite-containment measures.
Dust mites are members of the same family as spiders. Too small to be seen with the naked eye, they find a home wherever humans live. Dust mites don’t ask for much in life. They feed on any protein that comes their way and find easy pickings in the dead skin scales that humans shed every day. Apart from this simple diet, they need only a moderately warm, moist atmosphere, with a temperature of 65°F or higher and humidity around 65%. Bedding is the ideal dust mite home; after all, bedding offers warmth, sufficient moisture, plenty of skin, and fibrous materials to which dust mites can cling with their barbed legs. They also thrive in upholstered furniture, clothing, soft toys, and carpets.
The dust mite eats and excretes pellets of feces that are about the size of pollen grains, and finds other dust mites, with which it produces many offspring. Their fecal pellets enter the general household dust to become the main source of allergens. Eventually, as mites die off, their dried-out carcasses, composed of allergenic proteins, also join the dust. Over years, they can add many pounds to the weight of a mattress.
Keep Humidity Low to Discourage Mites
Dust mites flourish when the humidity is around 75% to 80%. These tiny cousins of spiders need water to survive but have no means of conserving it in their tissues. When the surrounding humidity falls below 50%, mites soon shrivel up and die. Thus, reducing household humidity can drastically reduce the dust mite population. A dehumidifier is useful for drying out the air. Take care to empty the water pan daily and scour it to stop the growth of microscopic molds.
Humidifier Use Can Promote Growth of Mites and Molds
Any increase in humidity, such as when a humidifier is used, will encourage mites and molds to grow in your child’s room. If your child has problems with croup or other breathing difficulties, ask your pediatrician’s advice about the best way to ensure that the air in the bedroom is moist enough to breathe comfortably but dry enough to discourage mites and molds.