HOUSE MITES – A CAUSE OF PERENNIAL ALLERGIC RHINITISAlthough they are just one of many forms of insects with whom we share our living quarters, mites are the most important from an allergy perspective. A subclass of arachnids, two species of these microscopic creatures account for the majority of “house mite” allergies: Dermatophagoides pteronyssinus and Dermatophagoides farinae. One or both may be present in a home at any time. Cleanliness of the home or its occupants has nothing to do with their presence.Mites need three things to survive: food, proper conditions of humidity, and safety. All three are found in homes. Their primary food source is shed skin cells from the human inhabitants and pets or feather-stuffed bedding and furniture. Skin shedding occurs in areas where humans spend the most time when at home, so there is good reason why the highest concentration of mites is found in stuffed furniture, carpeting, mattresses, and bedding. They also accumulate in clothing and stuffed toys.The old saying “safe as a bug in a rug” should be the house mite motto. These microscopic creatures burrow deep into upholstered furniture, stuffed toys, bedding, and loose, long-pile carpet. Here, moisture conditions are optimal for survival and the mites are sufficiently protected so as to be impervious to vacuuming and other human efforts to eradicate them. Or, at least they were.Modern living – central heating, better sealed homes, and wall-to-wall carpeting – has benefited both man and mite. Mites require very specific conditions of humidity in relation to temperature for survival. Ideal conditions encompass a relative humidity of 55 to 75 percent over a temperature range of 59 to 95 degrees F. What better place than a home at 70 degrees F and a relative humidity of greater than 60 percent? Still, because temperature and humidity conditions vary greatly throughout the United States, the concentration of mites is greater in some areas than in others.Mites have no lungs. They take air and water into their bodies primarily by diffusion through their shells. Thus, the greater the relative humidity, the greater their ability to acquire water. Their humidity needs are generally satisfied indoors, particularly in the winter months when the central heating system is functioning. In general, a combination of relative humidity of 40 to 50 percent and a temperature of 82 to 83 degrees F (28 to 34 degrees C) prohibits mite survival. So, whereas mites are found in most homes in the states bordering the east and gulf coasts, they occur in only a minority of homes in the states along the Rocky Mountains.People are allergic to the mite fecal pellet. A single mite will produce some 200 times its weight in these potent, highly allergenic fecal pellets during its short lifetime (about 4 weeks). Once expelled, the pellets break down, incorporate into the dust of the house and become airborne when the carpet, bedding, furniture, and so on are disturbed. Microscopic in size, these particles are easily inhaled into the nose and lungs, where they trigger allergy symptoms. The density of the live mite population in your home determines the degree of problem you will have with mite fecal particles. Although dead mites and their body parts do become airborne, they do not contribute significantly to mite allergy.*17/322/5*

Smoking may create or aggravate existing respiratory allergy because cigarettes may contain (besides tobacco) many potentially allergenic ingredients, such as licorice and molasses.

An allergic person, child or adult, should avoid small rooms and enclosed spaces where crowds gather and smoke (such as the smoking section of movie houses) because hot tobacco smoke is a nonspecific irritant besides being a potential allergen.

Pyrethrum

Pyrethrum is a powder prepared from the dried flower of the pyrethrum plant, which is related to the ragweed plant. It is used as an insecticide to spray plants in backyards or in moth killers to preserve winter clothing and carpeting.

Kapok

These fibers are used for filling life preservers (because they remain afloat for hours without much absorption of water); for insulation purposes; and for less expensive sleeping bags and mattresses. (Kapok was used in the past as a filling for pillows to avoid highly allergenic feathers. However, this practice has now stopped because of the development of foam rubber, plastics, and synthetic fibers.) Kapok seeds provide an oil used in making soap and in the preparation of certain foods.

Flax

Flax is the Latin word for the linen plant which provides linseed oil and linen fibers. Linseed oil may cause allergies when eaten, inhaled, or touched, and linen fibers may cause eczema and rashes when they are used in clothing.

Flax fibers, seeds, or oil may be inhaled when one is near flaxseed meal (which is a food given to cattle and poultry) ; in beauty salons and barber shops (as some wave sets, shampoos, and hair tonics (Kreml) may contain it); using bird lime, carron oil, flaxseed poultices, furniture polish, linseed oil, paints, varnishes, linoleum, printer’s and lithographic ink, some soft soaps, and some depilatories; or using damask, table linen, cambric, handkerchief linen, toweling, oilcloth, and sewing thread.

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Research shows that over a third of people in pain get relief from inert

tablets that they believe to be painkillers. Headaches, migraine, insomnia, epilepsy and rheumatoid arthritis are among the conditions that are susceptible to placebos.

In some cases, the symptoms may have been psychosomatic in origin, which would account for the good effect of the placebo. It may be that the patient feels gratified by someone taking his or her illness seriously, or it may simply be the power of suggestion – because they feel they are being offered a cure, they actually begin to get better. In other cases, there may be a mixture of organic illness and psychosomatic illness behind the symptoms – the two can coexist, one feeding on the other. Again, the placebo could be powerful because it meets some psychological need for attention and treatment.

With diseases such as rheumatoid arthritis, it is less obvious how the placebo effect works. However, the immune system plays an important role in rheumatoid arthritis, and this may provide a clue. A new form of treatment, or a new and more enthusiastic doctor, may act as a morale-booster which has a beneficial effect on the immune system – the sort of effect that the psychoneuroimmunologists are currently studying. Placebo effects are also seen in allergy, perhaps for the same reason.

A characteristic feature of the placebo effect is that it does not last all that long: it is usually only a matter of weeks, and two to six months is about the most that can be expected. If a patient responds to a new treatment and is still well after a year, it is unlikely to be a placebo effect.

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