The Mayo Clinic in America estimates1 the average bed contains between 100,000 to 10-million dust mites. The reason is dust mites ─ those tiny bugs that live in linen2 and pillowcases3 and feed on your dead skin ─ and the problems they can cause when you press your face into them for months at a time.

"When you're in your bed, the mattresses, bed sheets and pillows get both warm and humid4 ─ an environment the critters like, so they thrive there." the clinic's Web site cautions.

Dust mites, or the feces or decaying body parts they leave behind are more irritating than other allergens. Like allergy5 season, only worse. 

The solution is allergen-proof encasements ─ zipperd cases made of vinyl or tightly woven fabric that act as barriers against dust mite allergens. People are encouraged to wash their linens weekly in hot water over 130 degrees Fahrenheit.

美國梅佑醫學中心估計，平均每張床藏納十萬至一千萬隻塵蹣。因為塵蹣是以人類掉落在床單與枕頭套的皮膚屑為生的小蟲，以及及數月來每次把臉壓在牠們身上時可能造成的問題。

該中心的網站提醒，當躺在床上時，床墊、床單與枕頭就變得既溫暖又潮濕，是塵蹣這種生物喜好的環境，因此牠們就繁殖起來。

塵蹣或其排泄物，抑或其腐壞的組織，比其他過敏原更惱人，如果在過敏季節，情況會更糟。

解決之道是找防過敏原的床單床罩組（乙烯基製作的拉鍊床組或可阻隔塵蹣過敏原的細緻織品），鼓勵大家每星期以華氏一百三十度以上的熱水清洗床單。