Dust Mite Allergy

This information was reviewed and approved by Carah Santos, MD (12/6/2022).

Dust mites are microscopic animals that feed on human skin scales. They live in bedding, carpets, stuffed furniture, old clothing and stuffed toys. Dust mites are most common in humid climates and don't survive when the humidity is below 50%.

Almost everyone is exposed to dust mites, but not everyone is sensitive to them. Most significantly, children allergic to dust mites are five times more likely to develop asthma. If droppings of dust mites are inhaled or come in contact with the skin, they may cause allergic symptoms and aggravate asthma and/or eczema. Examples of allergy symptoms include itchy eyes, runny nose and rash.

Dust allergy actually is an allergy to the dust inside the home and the dust inside the home actually will contain any of the what we call perennial allergens, but then importantly dust mites are also included in dust. Dust mites love bedding so they love being in the bedroom, carpets, rugs, drapery and so it's very important to keep tabs on where the dust mites might be and try to prevent them because they can cause problems all year round in a place where we spend a lot of time which is our bedroom.

Dust mite allergy can cause symptoms of the nose, the eyes and particularly of the lungs in somebody who has allergic asthma. So your typical allergy symptoms, nasal itchiness, runny nose, post nasal drip, congestion and then again importantly a flare of somebody's asthma if they're dust mite allergic.

So testing for dust mite allergy involves a skin prick testing which is putting a drop of extract on the skin and then poking through it. We also have intradermal testing for more subtle allergy where a little bit of the extract will be actually placed under the skin and then there's specific IGE testing which is a blood test looking for IGE which is the allergic antibody and specific for dust mites.

Treatment for dust mite allergy generally involves limiting exposure to dust mites. So dust mites tend to love bedding and upholstered furniture, rugs and carpeting so trying to limit those in the home and trying to change to hardwood floor if at all possible, leather furniture. In terms of the mattresses and pillows where dust mites like to live we generally recommend wrapping them all the way around with a finely woven cover on the mattress and on the pillow and make sure that that cover zips up and then really tries to keep the dust mites away from the individual's face.

In addition there is dust mite allergen immunotherapy so allergy shots either traditional shots which can be mixed with the other allergens and now there's a newly approved sublingual immunotherapy as well so a tablet for dust mite allergy.

Dust mites live on human skin scales. People slough off dead skin cells all the time, and, in the process, dust mites infiltrate the soft surfaces of bedding, pillows, sofas and carpets. Because of this, the bedroom is the most important area to consider when taking preventive measures. Environmental control measures to consider include:

Enclosing mattresses, pillows and box springs in zipped, dust-proof encasings. Dust-proof encasings have a layer of material that holds the dust mites inside. Encasings are usually made of plastic or plastic-like materials. If there is more than one mattress in the bedroom, all should be encased. It is recommended that cloth tape be placed over the encasing zipper.
Washing all bedding in hot (130° F) water weekly
Avoiding lying on upholstered furniture or carpets
Removing carpeting from the bedroom. Instead, use area rugs that can be washed.
Using wood, leather or vinyl furniture instead of upholstered furniture in the bedroom
Vacuuming rugs and carpets frequently. The person with a dust mite allergy should not vacuum or be in a room while it is being vacuumed.
Keeping indoor moisture low. The ideal humidity level is 30-40%. Use an air conditioner or dehumidifier in warm climates to decrease the humidity. Clean the dehumidifier regularly.
Avoiding the use of humidifiers or vaporizers, because they will increase humidity in the room and create a favorable environment for dust mites
Applying an acaricide (a chemical solution that kills mites) regularly to carpeting and upholstery
Applying tannic acid solution to help neutralize the allergen in mite droppings

Dust Mites Thrive in Humidity

Since humidity is necessary for dust mites to reproduce, it is useful to know your home's moisture level. The easiest, least expensive way is to buy a hygrometer to assess indoor humidity. The humidity in your home should be below 40%. Humidity levels between 40 and 50% are marginal in terms of dust mite control. In the 50 to 60% range, dust mites can be bothersome, and they are even worse when the humidity is above 60 percent.

Air conditioning is an effective way to control indoor moisture. If you have an inside air conditioner, make sure you have good drainage, so there is no standing water inside or around the cooler.

Dust Mites in Bedding

Pillows and mattresses are prime habitats for dust mites. Use special allergen-impermeable casings for mattresses and pillows to keep allergens from reaching you. Weekly washing of bedding in hot water (at least 130° F) is also recommended. The casings can be purchased at stores carrying allergy-related items.

Terrazzo and tile flooring also limit dust mite exposure. These floorings don't provide the soft nesting areas that carpets do.

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