House dust mites reproduce best in warm conditions and humidity of over 50%. For this reason the Swiss Allergy Centre (aha!)
recommends keeping room temperature at a constant 19 to 21 degrees Celsius. Brief but intense airing ("inrush airing") can also help keep the humidity below 50%.
Mites feel most at home in mattresses and bedclothes, so here too you have to nip their activity in the bud, for example by using mite-proof mattress covers and washing your bedclothes at 60 degrees.
The bedroom's not the only place house dust mites make their home. They can also be found in the living room. The best precaution is not to have carpets, curtains or upholstered furniture in your living room, all places dust can gather. If you're allergic, you risk breathing in air containing allergens excreted by the mites in their faeces that have combined with dust.
If you live at more than 1,200 metres above sea level you can count yourself lucky, as the mites can't reproduce at such high elevation.
According to the Swiss Allergy Centre, the symptoms of house dust mite allergy are typically a blocked nose, sneezing, a runny nose and red eyes. They mainly occur in the morning. The aha! website also says that skin rashes and allergic asthma are possible delayed reactions.