How can they be controlled?
Various products claim to help eliminate dust mites. In fact, many acaracides have been field tested in clinical trials, including
pyrethroids, organochlorides, benzyl benzoate, thiabendazole, triclosan, silver and tributyltin oxide. Most have been unsuccessful.
For example, permethrin-treated carpets showed no success in reducing dust mite numbers. With benzyl benzoate, the exact acaracide
mechanism of action is unknown but is thought to be a gut poison to dust mites. It works via contact and lethal ingestion
by the mites. Laboratory trials show benzyl benzoate to be highly effective, but field trials have been disappointing. The
chemical was unable to penetrate fabrics at the manufacturer's suggested dose and application time yet showed some success
when applied at a higher concentration and left down longer (four hours vs. 12 hours).
Other treatments such as dehumidifiers reduced the humidity of room air, but the upper layers of the carpet and mattress still
had the required humidity needed by dust mites to feed and reproduce. Steam cleaning has been found to be helpful, but ultraviolet
light treatments have not been studied as of yet.
So what are some simple proven methods of controlling dust mites in the home? Washing bedding, cloth toys and fabrics at least
once weekly in hot water (> 50 C) or cold water adding tea tree oil or benzyl benzoate is helpful. Vacuuming picks up dead
mites because the live dust mites actually attach and hold onto fabrics. As an adjunct to other methods, vacuuming using a
HEPA filter can be helpful, but without a HEPA filter, it can actually make matters worse. Mattress and pillow covers serve
as barriers and along with the above suggestions, can be helpful. Airing bedding out in the hot sun or cold weather for a
good l2 hours has also shown to reduce dust mite numbers. Replacing dog beds at least every six months and washing them along
with cloth toys as per the above instructions at least weekly is a good idea.
Ultimately, treatment of dust mite allergy with immunotherapy, cyclosporine or antihistamines provides the most relief for
our allergic patients. Discussing the facts and fallacies of environmental treatment with clients can save them time and money
by avoiding unsuccessful methods.
Dr. Jeromin is a pharmacist and veterinary dermatologist in private practice in Cleveland, Ohio. She is a 1989 graduate of The Ohio State
University College of Veterinary Medicine and an adjunct professor at Case Western Reserve University's College of Medicine
For more information: Colloff M. Dust mites. Csiro Publishing, Australia, 2009.