House Dust Mites

Environmental and Occupational Health Pearls - March 2017: House Dust Mites

A bi-monthly feature providing clinical information and resources from Public Health Ontario on matters relating to environmental and occupational health. This edition considers the most important questions about lead exposure for family physicians.

House dust mites (HDM) are tiny arachnids that are everywhere in homes worldwide and feed on flakes of dead skin. They do not bite humans or spread disease. HDM droppings contain proteins that can be allergenic, provoking allergic rhinitis, asthma exacerbations, atopic dermatitis and wheezing or coughing. HDM are more common in warm and humid areas and are often found in carpeting, bedding, furniture and stuffed animals.

How can Family Physicians respond?

While environmental avoidance measures including the use of mattress covers, frequent vacuuming and mopping have been suggested, systematic reviews have failed to find evidence of effectiveness of these measures in controlling asthma or eczema1,2.  This may be because most exposure to HDM aeroallergen occurs during the day3. While medical management of HDM allergy is effective, family physicians should take care not to raise unrealistic patient expectations by advising environmental avoidance measures that are of unproven benefit.

For more information, see the following reference articles:

1. Gotzsche PC, Johansen HK. House dust mite control measures for asthma: systematic review . Allergy 2008: 63:646-659.

     2. Nankervis H, pynn EV, Boyle RJ, Rushton L, Williams HC, Hewson DM, Platts-Mills T. House dust mite reduction and avoidance measures for treating eczema (Review).  The Cochrane Library 2015, Issue 1. 

     3. Tovey ER, Willenborg CM, Crisafulli DA, Rimmer J, Marks GB. Most personal exposure to house dust mite aeroallergen occurs during the day. PLOS One 2013: 8(7)e69900.