Dust Mite Covers May Not Help Dust Mite Allergy

Dust Mite Covers May Not Be Worth the Cost

Do dust mite covers do any good?. ADAM

Allergic diseases, such as allergic rhinitis, atopic dermatitis and asthma, are becoming more common over the past 50 years. Allergic rhinitis now affects up to 30% of the population, especially children and young adults. Atopic dermatitis, often the first manifestation of allergic disease, can affect up to 30% of young children and 10% of adults in certain parts of the world. Asthma is becoming more common as well, and affects 8% to 12% of the population.

The most common allergic trigger worldwide for these various conditions is the house dust mite (HDM), which causes allergy in 30% of people with various allergic conditions.

Current Recommendations on House Dust Mite Avoidance

Avoidance of HDMs is the first approach to the treatment of allergies caused by this allergen. Typical avoidance measures include frequent washing of bedding in hot water, regular vacuuming, and covering pillows and mattresses with dust mite covers (or dust mite casings) that are impermeable to HDMs. These dust mite covers act to trap HDMs inside the pillow and mattress, where they accumulate, away from the person with a HDM allergy. Dust mite covers are available at many retail outlets, as well as online stores, at a substantial cost. Most allergists, including myself, have recommended dust mite covers for years to people allergic to dust mites.

Are Dust Mite Covers Helpful for Treating Dust Mite Allergy?

Recent studies have questioned the benefits of dust mite covers for both the prevention of developing HDM allergy (sensitization) as well as for the prevention of symptoms caused by HDM allergy.

While many national and international health organizations continue to recommend HDM covers to reduce allergic symptoms caused by HDMs, other health organizations feel that there is insufficient evidence to do so. A recent study, published in 2014 by public health officials at Tulane University in New Orleans, sought to compile data from dozens of studies (called a meta-analysis) involving thousands of patients to determine if HDM covers are helpful for the prevention or treatment of HDM allergy.

The results of the meta-analysis were quite surprising. Taken together, the studies showed that the use of HDM covers were not helpful for the primary prevention of allergic disease (asthma, allergic rhinitis or atopic dermatitis) or for the prevention of sensitization to HDM. The meta-analysis also failed to show that the use of HDM covers were useful for the tertiary prevention of allergic disease – meaning that symptoms of allergic disease (asthma, allergic rhinitis or atopic dermatitis) did not improve in patients who already had those diseases.

HDM covers were useful in reducing the amount of HDM allergen found in the mattresses, which proves that the HDM covers did their job, but this did not result in a significant improvement in symptoms. This is likely due to the fact that while HDM levels were reduced with the use of HDM covers, these levels did not fall below the threshold level needed to cause allergic disease.

Therefore, I plan to change the way I discuss HDM avoidance with my patients who show an allergy to HDM on skin testing: I will continue to recommend the frequent washing of bedding in hot water, as well as regular vacuuming, but I will state that the benefit of HDM covers is unproven, and that the cost may outweigh the benefits.

Learn more about dust mite allergy.


Arroyave WD, Rabito FA, Carlson JC, et al. Impermeable Dust Mite Covers in the Primary and Tertiary Prevention of Allergic Disease: A Meta-Analysis. Ann Allergy Asthma Immunol. 2014;112:237-48.

Continue Reading