Allergen avoidance measures in the home
Studies presented at the annual meeting of the American Academy of Allergy, Asthma and Immunology (March 13th-18th in Washington, DC) confirmed the importance of environmental exposure to furred pets, cockroaches, and dust mites in causing and worsening of asthma in children. Allergens (substances causing the allergic response) are difficult to avoid completely, but certain measures can help lower exposure to important indoor allergens, especially dust mites.
Allergen avoidance measures are not only important for those children who have allergies and asthma, but also for those children who are born into "allergic families." Studies done in the past have suggested that the less allergen children are is exposed to, the less chance they have of developing asthma during their childhood. Several studies presented at the annual meeting revealed practical information on allergen avoidance.
Three studies showed that maintaining humidity in the home to less than 50-55% can significantly retard dust mite growth. These studies showed that even a few hours of higher humidity in the home lead to increased dust mite levels. This information suggests that constant use of air conditioning and possibly dehumidifiers is beneficial.
One study looked at laundry methods, since it has been shown in the past that bedding, pillow covers, and clothing are important sources of dust mite. In summary, it appears that hot water (at least 122 degrees), regardless of whether detergent or bleach is used, is effective in killing dust mites. Since it may not be safe to have the water heater turned up so high in homes with small children, these researchers looked at bathing the laundry in bleach with 95 degree water. After one hour of this bleach bath, most of the dust mites were killed. Detergent alone in warm water over long periods was not able to kill the mites sufficiently.
Various studies confirmed that previously recommended dust mite avoidance measures were effective, such as plastic encasements for mattresses and pillows (to keep dust mites from getting out) and the use of double thickness vacuum cleaner bags. It is still thought, however, that removal of carpeting in the bedroom of allergic children is the best method of dust mite avoidance from carpets.
Two studies revealed some bad news about efforts to avoid cockroach allergens. Very aggressive means to eradicate roaches did not show any significant benefit. Further research in conjunction with the exterminating industry is planned in this area.
Lastly, one study showed that washing dogs (2 or 3 times per week) can decrease allergen exposure. Some studies in the past have shown that regular washing or the application of a damp cloth to cats can have a slight effect, while other studies showed these measures to be ineffective. Obviously, the ideal situation is removal of the allergy-causing furred pet. Most Allergists realize, however, that most families would rather part with their doctor than their pet.