Nasal allergy symptoms (rhinitis) and asthma caused by allergens that are inhaled usually have seasonal patterns. While symptoms from various pollens occur in the spring, summer or late summer/fall, nasal allergy symptoms in fall and winter are due mainly to indoor inhalants and also usually seasonal. But in the case of indoor allergens, this seasonal pattern is the result of spending more time indoors in these months, with the windows closed and heat on, leading to both increased exposure times and increased levels of indoor allergens.

Dust mites—microscopic insect critters that live in our bedding—are the most important culprit among the indoor allergens causing allergic disease. Our pillows and mattresses are loaded with them. When you buy a new mattress that weighs, say, 100 pounds, it will weigh 102 pounds within a couple of years. That extra 2 pounds are from the accumulation of living and dead dust mites and their droppings. Fortunately, dust mites do not bite, though in addition to their role in causing nasal allergy and asthma, they probably also contribute to flares of eczema in certain patients.

Why Dust Mites Love Us

The diet of a mite consists mainly of human skin scales, of which we shed a lot in the course of a day. This is why they love our bedding.

The life cycle of dust mites is related to humidity. They love the humid days of summer and proliferate wildly. Then, when the heat goes on indoors in autumn, the humidity falls and they die off, leaving additional particulate matter to breath in.

If you want to read some of the scientific research on dust mites, Google the name “Thomas Platts-Mills,” who is a world expert on mites and gives very entertaining lectures on the subject.

Diagnosis

There is no way to know if one is allergic to dust mites without being tested. If you tested positive to “house dust” years ago (a test most allergists don’t do anymore), you should be tested again. Since house dust is a mixture of dust mites, animal dander, insect material and other dusts, allergy to any of these components would have resulted in a positive house dust test. Today, we test for the individual components of house dust.

Treatment

1. The treatment for dust mite allergy is, first and foremost, avoidance.

Bedding ­– Various companies market breathable covers that seal the bedding. Mite covers have even been shown to reduce the risk of developing asthma for children born into families with a history of allergic disease.

Humidity – The use of humidifiers in most houses in winter is not recommended, as it encourages mite growth. Optimal humidity in the home of someone with respiratory illness is in the 30% to 40% range; most homes are within that range or higher in winter. If you are not sure, you can measure it with a hygrometer.

2. The second line of treatment is medication for the symptoms of rhinitis, asthma or eczema. These include various combinations of prescription and over-the-counter medications, including pills, nasal sprays, eye drops and, in the case of eczema, creams and ointments. Antihistamines (ocular and oral) are the only medications for rhinitis that are available over the counter without a prescription. Any over-the-counter medications for asthma should be avoided, particularly Primatene, which is not very safe.

3. For patients who do not respond sufficiently to the above measures, or those wishing to reduce their use of medications, immunotherapy (allergy injections) might be in order.

I hope your holiday season is happy, and that you can avoid the sneezin’ and wheezin’!

To find an allergist who is right for you, please call the Physician Referral Service at 1 (866) 804-1007 Monday through Friday, 9 am to 5 pm.