All you need to know about the house dust mite
For the Curious

Six kinds of asthma, dust mites can affect them all

The six different types of asthma are: allergic (most common); occupational (work associated); steroid resistant (severe asthma); drug related; exercise induced and asthma related to obesity. Although they are separate they can work together to make asthma worse. Exposure to dust mites can impact on all of these.
1. Allergic asthma is the most common form of the disease and both storage and house dust mites are known worldwide as a cause of allergy symptoms.

2. Occupational asthma can come from a wide range of substances, but can also be caused by exposure to dust mites at work. Patients at risk can be domestic cleaners, visiting health care workers, veterinary staff or field and farm workers handling mite-infested animals, hay or crops.

3. Steroid resistant asthma patients have been shown to have a form of asthma that can be driven by neutrophil immune reactions, which are known to be less responsive to steroid treatments. New research indicates that house dust mites can trigger a neutrophil, as well as the 'normal' allergic eosinophil inflammatory reaction. If proven correct this makes mites 'double trouble' for the vulnerable steroid-resistant asthma patient.

4. Drug related asthma mainly refers to aspirin or NSAID (non steroidal anti-inflammatory) medication to relieve pain. The patients are not allergic to the drug itself, but vulnerable to the effect it has on the body. In some patients, NSAID drugs can increase the absorption mechanism of the gut, resulting in an increased uptake of environmental elements, including allergens. Dust mite-contaminated wheat or corn flour in baked food has been blamed for NSAID related severe allergic events in patients already allergic to mites.

5. Exercise induced asthma (EIA). The tubes that bring air into and out of lungs narrow with exercise. The temperature or quality of the air breathed in during exercise can cause symptoms of asthma in people not otherwise diagnosed with asthma. The symptoms are wheezing, coughing, or shortness of breath during or about 20 minutes following exercise. Preparations, such as a warm-up routine before exercise, can reduce EIA. Patients, already diagnosed with other forms of asthma need to take extra care or their asthma can get worse. This includes an active allergy to dust mite exposure.

6. Obesity, combined with atopy (the ability to easily make IgE) or allergy is associated with symptoms of asthma. Dust mites can induce atopy (which can lead to allergy) and trigger allergic immune responses including asthma.


References

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The Importance of Storage Mite Allergens in Occupational and Domestic Environments, John Chambers, B Bhushy Thind, Jackie A Dunn, David J. Peason, Proceeding of the 3rd International Conference on Urban Pests. Wm. H Robinson, F Rettich and G.W. Rambo (editors). 1999.

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'Dust mite ingestion-associated, exercise-induced anaphylaxis', Sanchez-Borges M, Iraola V, Fernandez-Caldas E, Capriles-Hulett A, Caballero-Fonseca F, J. Allergy Clin. Immunol. 2007 Sept; 120(3):714-6

Obesity, insulin resistance and the prevalence of atopy and asthma in US adults, Ma J, Xiao,S, Knowles S.B. Allergy, 2010, Vol. 65; Issue 11: p1455-1463