House dust mite
House Dust Mite (Dermatophagoides pteronyssinus)
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: Animalia : Arthropoda : Arachnida : Acarina : Pyroglyphidae : Dermatophagoides : pteronyssinus
Binomial name
Dermatophagoides pteronyssinus

The house dust mite (Dermatophagoides pteronyssinus), sometimes abbreviated by allergists to HDM, is a cosmopolitan guest in human habitation. Dust mites are approximately one third of a millimeter in size, and have eight legs like spiders, not six legs like insects. They are a member of the arthropod phylum.

The house dust mite is more common in Europe than North America, where it is replaced by D. farinae. The mite thrives in modern fully-carpeted, double-glazed, draught-proof homes, and is comfortable at 25C, 75% relative humidity. The mite lives on shed human skin cells, predigested by the fungus Aspergillus repens . It is particularly common in carpets and bedding. An average person sheds about 1.5 grams of skin a day (about half the mass of a penny), which is enough to feed roughly a million dust mites.

The house dust mite is one of the most important allergens, implicated in allergic asthma, rhinitis, conjunctivitis and dermatitis. The protein responsible for the allergic reaction is DerP1, a protease digestive enzyme found in mite feces.

Measures to control house dust mite include:

• Regular vacuum cleaning (especially with high-efficiency particulate air (HEPA) filters)
• Regular damp dusting of surfaces
• Replacement of carpets with vinyl flooring
• Covering of mattresses and pillows with impervious materials
• Daytime internment of teddy bears in a freezer
• Use of chemicals (acaricides) to kill mites
• Use of fungicides to kill Aspergillus

These measures, while reducing numbers of HDM and amounts of allergen, seem to have only marginal effects on allergic symptoms.

External links

• House Dust Mite Avoidance in Asthma: Cochrane
• House Dust Mite Avoidance in Rhinitis: Cochrane
• Dust Mite Allergy Tips
• HouseDustMite.org