Dust Mites & Their Fecal Pellets (click to enlarge) Dust mite has 8 legs with claws. It is about 0.25mm (0.01 inch) long.   Dust mites are one of the most numerous uninvited guests in our home. Their fecal pellets cause allergic reactions for a lot of people. Dust mites thrive in warm moist environment. Just a single mattress or carpet may contain thousands or even millions of them.   Dust mites have eight legs with claws that can grasp tightly onto the mattress fabric. Hence it requires professional-grade cleaning system to remove them. However, the popular filter-based vacuum cleaners are not effective in removing dust mites, and they disperse the dust particles through the pores of the dust bag or filters, causing allergies and other health problems.   Characteristics of dust mites include:   About 0.25mm (0.01 inch) long. They are usually invisible to the naked eyes.   Rapid reproduction cycle: It takes about a month for a dust mite egg to hatch and the mite to mature to an adult. An adult female mite may live another month and lay about 200 eggs in skin-ladden house dust.   Can survive in temperatures above 15°C (60°F) and in a relative humidity above 50%. The ideal temperature is around 25°C (77°F). The ideal relative humidity is between 75 - 80%.   Do not need to drink to satisfy their thirst. They absorb water directly from the air through special glands in their skin.   Can be killed by hot water at a temperature above 55°C (130°F). Therefore it is advisable to use bedding items that are washable in water. The pillow, mattress and duvet can be protected by zipped and tightly-woven cotton bedding covers that can prevent dust mites from passing through.   Common items that trap dust mites Mattress & pillow   Fabric sofa / chair   Carpet   Stuffed toys   Thick clothing         In bed, we provide the moisture required by dust mites from our skin and our breath. When we breathe into our pillows, mites congregate to inhale the moist air. Warm quilts and soft mattress pads soak up our body moisture and sweat, feeding the growth of not only dust mites, but also mould and bacteria. Dust mites feed on shed human skin, pollens, mold spores etc. We shed about 30 grams of skin scales each month, so the food supply for dust mites is virtually infinite. Our shed skin scales are small enough to pass through the cotton weave of pillow cases, bed sheets and mattress pads, and they accumulate inside our pillows and mattresses. Even rarely washed thick winter clothing may harbour a significant population of dust mites.   Allergens from Dust Mites People are not allergic to dust mites themselves but to their fecal pellets, which contain allergenic materials such as mite digestive enzymes or mold spores. These fecal pellets may enter the body through the mucous surface of the nose, the lining of the eyes, or the lining in the airways of the lungs. The fecal pellets of dust mites are sticky materials that bind to fabric of mattress, carpet and upholstery. Being so light and tiny, the fecal pellets can be disturbed by everyday actions such as sitting on a bed or an upholstered sofa, and they remain airborne for at least 30 minutes before settling once more. One of the worst ways to bring dust mites allergens into the air is to vacuum the place with a filter-based vacuum cleaner, which blows out the allergen particles through the pores of the filter or dust bag. The dust mite allergens can float in the air for a couple of hours and makes up the motes in a beam of sunlight. (The particles seen floating in a shaft of sunlight are dead dust mites, their waste products and skin flakes shed form human bodies.)   Dust Mites Disrupt Skin's Protective Function, Causing Severe Skin Diseases A research in Japan found that dust mites and their droppings contain an enzyme, which damages the skin's protective function, making it vulnerable to attack by other allergens or pathogens. Many patients only go to the hospital for treatment after they have developed severe skin diseases, without knowing why. Effective removal of dust mites from the home environment is essential in the prevention of skin irritation and skin diseases. (learn more)   Species of Dust Mites There are over a dozen common species of mites found in houses. People tested with negative reaction to one type of dust mites does not rule out allergy to other species. Examples of common species include: Dermatophagoides pteronyssinus and Dermatophagoides farinae are 2 of the most popular species Cheyletus eruditus, one species of dust mite, preys on other dust mites. Glycyphagus domesticus is called grocers itch mite because it thrives on flour and wheat. Tyrooglyphus farinae is called a storage mite as it lives in stored grains.