Dust mite

The house dust mite may be an important year-round cause of atopic dermatitis (eczema) and asthma.

Dermatophagoides pteronyssinus, the house dust mite, can only be seen with a microscope but it is nevertheless a common and significant cause of allergy. It may make the nose run or cause sneezing and wheezing. In some patients it also contributes to exacerbations of atopic dermatitis.

The dust mite hides in the dust that can be found in even the cleanest bedroom – deep in carpets and curtains and in the seams of mattresses, where even the most house-proud individual can't find it. It thrives in poorly ventilated and humid homes.

Bedding

• The dust mite's favourite haunt is bedding, particularly mattresses. If sleeping in a bunk, an allergy-prone child is best on the top mattress.
• The dust mite may be found in high concentrations in bedding made from wool, cotton and artificial fibres. Wash and dry the sheets every week.
• Obtain special mite resistant covers for pillow, mattress and duvets.
• Wash the bedding in hot water (at least 54 Celcius) regularly or use a dust mite control laundry additive.

Measures to reduce the numbers of house dust mite.

• Use a vacuum cleaner that has a HEPA filter. Vacuum all carpets each week, especially in the bedrooms and under the beds. If you can, choose vinyl flooring rather than carpet as it tends to hoard less dust. Vacuum upholstery and curtains, and don't forget the mattress and blankets.
• Use a damp duster to do the cleaning as it is much better at collecting dust than a dry one.
• Wash curtains regularly. There is less dust when curtains are made of lightweight materials. They also need to be vacuumed often, and wash them regularly too (perhaps six-weekly).
• Hang clothes up in wardrobes, and that includes the dressing gowns! Make sure the wardrobe is well ventilated, or consider a chemical moisture remover such as anhydrous calcium chloride flakes.
• Dehumidifiers can reduce numbers of house dust mites, as they prefer a moist environment.
• Put soft toys in the freezer for a few hours.