Although the exact mechanisms behind the development and progression of atopic dermatitis are unknown, it has long been established that certain allergens, including dust mites, are a potential trigger for the condition.1-3 Despite this apparent link, the complex relationship between dust mites and AD is not well understood and may be a combination of internal and external factors.
What are dust mites?
Dust mites are tiny arthropods (the same group that spiders belong to) that live in many homes. Dust mites are less than a third of a millimeter in length, making them too small for humans to see with the naked eye. Dust mites feed on the dead skin cells that humans shed each day. They favor more humid households; however, they can thrive across many different humidity levels and in temperatures ranging from 60 to 80 degrees Fahrenheit (including average household room temperatures). Dust mites can live all over in the home, however, they may be found in larger concentrations in areas that have a higher volume of skin shedding, such as the bed, sofa, or carpet. Dust mite-related allergies in humans may be caused by the dust mites themselves, or the waste products they create while breaking down dead skin cells.1
What is the connection between dust mites and AD?
As mentioned, the connection between dust mites and AD is not well understood, partly because the mechanisms behind AD are not well characterized. Some theories center around dysfunction in the skin barrier that allows dust mite entry into the body more easily.4-5 However, other theories center on the immune system response to dust mites internally. One such study investigated the level of CD1a molecules in the body, which respond to the extract-of-house-dust-mite used in allergy testing. CD1a molecules are thought to be involved in the immune system response that leads to the development of an allergy. CD1a molecules, in this case, are thought to respond to the waste products created from dust mites as they break down skin cells. In one study, individuals with AD were found to have higher levels of CD1a than individuals without AD, indicating that sensitivity to dust mites may be on a molecular, and immune system-related level.5
A connection to the microbiome?
Other internal and immune system-related theories on the relationship between dust mites and AD center on the bacteria within the gut. Certain species of bacteria within the intestines are thought to produce different immune system responses. One scientific review investigated the use of probiotics (good bacteria that can be added to food or supplements and impact the gut bacterial environment) and the development or reduction of dust mite-related AD. The data analyzed pointed toward a reduction in the development and symptoms of dust mite-related AD when treatment with probiotics was initiated at specific times. This indicates that sensitivity to dust mites may be related to an internal immune system process that is heavily influenced by the bacteria in the gut.6 On a similar note, another study pointed toward a decrease in vitamin D levels (a key immune system regulator) in connection to severe dust mite-related AD.7
More research is still needed
It’s important to note that is not an exhaustive outline of all theories on the relationship between dust mites and AD. Much more research is needed to strengthen the theories listed, and the actual relationship may be a combination of several different theories. As an example, dysfunction in the skin barrier may lead to increased penetration of dust mite-related particles through the skin, which may then be susceptible to a faulty immune response. However, more investigation is needed to understand the complex factors involved in these processes.
Are there any ways to reduce AD flares caused by dust mites?
Currently, there is no scientific consensus on preventative measures against dust mites in relation to their ability to trigger AD.8,9 Despite this, there are tactics that can be used to potentially reduce the amount of dust mites and dust mite-related waste in your home. These include:
Using vacuums with special filters, such as HEPA filters, that are designed to remove dust mites and their waste products efficiently (these filters can also be used with central furnaces and in air conditioning units)
Reducing the amount of carpet, curtains, and other fabrics that commonly collect dust
Dust Mite Allergy. Asthma and Allergy Foundation of America. http://www.aafa.org/page/dust-mite-allergy.aspx. Published October 2015. Accessed July 3, 2018.
Atopic Dermatitis and the House Dust Mite. https://www.aaaai.org/global/latest-research-summaries/Current-JACI-Research/atopic-dermatitis-dust-mite. Published October 10, 2013. Accessed July 3, 2018.
Park KH, Lee J, et al. Sensitization to various minor house dust mite allergens is greater in patients with atopic dermatitis than in those with respiratory allergic disease. Clinical and Experimental Allergy. Abstract available from: https://onlinelibrary.wiley.com/doi/pdf/10.1111/cea.13164. Published April 27, 2018. Accessed July 3, 2018.
Atherton DJ. The role of house dust mites in the etiology of atopic dermatitis. Eur J Pediat Dermatol. 1991; 1(1), 41-44.
Jarrett R Salio M, et al. Filaggrin inhibits generation of CD1a neolipid antigens by house dust mite-derived phospholipase. Science Translational Medicine. 10 Feb 2016; 8 (325), 325ra18.
Fassio F, Guagnini F. House dust mite-related respiratory allergies and probiotics: A narrative review. Clinical and Molecular Allergy. 19 June 2018; 16(15). Available from: https://clinicalmolecularallergy.biomedcentral.com/articles/10.1186/s12948-018-0092-9. Accessed July 3, 2018.
Jang YH, Sim HB, et al. House dust mite sensitization is inversely associated with plasma 25-hydroxyvitamin D3 levels in patients with severe atopic dermatitis. Ann Dermatol. 2017; 29(4), 400-406. Available from: https://anndermatol.org/Synapse/Data/PDFData/0140AD/ad-29-400.pdf. Accessed July 3, 2018.
Bremmer SF, Simpson EL. Dust mite avoidance for the primary prevention of atopic dermatitis: A systematic review and meta-analysis. Pediatric Allergy and Immunology. Nov 2015; 26(7), 646-54.
Nankervis H, Pynn EV, et al. House dust mite reduction and avoidance measures for treating eczema (Review). The Cochrane Collaboration. 2015. Available from: https://pdfs.semanticscholar.org/cb27/3f91d047feaa49d26b06292e6450500242a4.pdf. Accessed July 3, 2018.