Many people suffer from a runny or stuffy nose, watery or itching eyes, sneezing, and sinus pressure in the winter months. Are these symptoms related to the common cold or allergies? While it may be difficult to tell based on symptoms alone, if your symptoms persist for more than a week, you may have an allergy, according to Shradha Agarwal, MD, Assistant Professor, Department of Medicine, Division of Clinical Immunology, Icahn School of Medicine at Mount Sinai. Although pollen is not present in winter, the powdery substance is not the only cause of allergies.

Dust mites—microscopic eight-legged arachnids found in dust—are a major source of in-home allergen. Mites burrow in soft material; are commonly found in clothing, pillows, blankets, and mattresses; and feed on human skin scales, fungi, yeast, and bacteria. They are sensitive to light and depend on water to survive. Mites are susceptible to water loss at humidity levels below 65 percent;  because of this, allergen levels increase in the summer and remain elevated through the winter. Depending on humidity levels and temperature, the average life cycle of a dust mite varies from 60-120 days. Although they live for a short time, the damage is done quickly. Female mites can lay 50-80 eggs in a lifetime. Dust mite allergies are prevalent in children and adults. Symptoms are caused by inhaling airborne particles of dust mite waste. This commonly leads to post-nasal drip, nasal congestion, sneezing, and/or runny nose. Inhaling particles can also trigger asthma-symptoms such as shortness of breath, wheezing, and coughing, and eczema.

Chemicals can be used to kill dust mites; however, this is not recommended. The effect is short term and requires repeated application of and exposure to harmful chemicals. The best strategy is to limit your exposure to dust mites. This is best achieved by:

• Keeping the relative humidity in your home between 35-50 percent. This reduces the growth of dust mites. If you plan to use a humidifier in the winter, monitor the humidity with a hygrometer and keep below 50 percent.
• Washing your bedding every week. This drowns mites, helping to reduce dust mite numbers and, consequently, mite allergen levels.
• Dusting and cleaning wood floors with a clean, damp cloth.
• Vacuuming regularly. High-efficiency particular air (HEPA) filtration helps decrease exposure to particles containing dust mite allergen.
• Removing stuffed toys, throw pillows, drapes, and carpeting/rugs from the floor.
• Using impermeable covers for dust mite on mattress and pillow encasing.
• If you have to clean yourself, wear a mask.

Dust mite allergies can be treated with medications such as antihistamines, decongestants, nasal sprays, and eye drops. If your symptoms are not well controlled with allergy medication, your doctor may advise allergy immunotherapy which can be administered by injection (subcutaneously) or orally (sublingual). Visit an allergist to determine if you have a dust mite allergy.

A complete history and skin prick/scratch testing or a blood test for antibodies to dust mite allergens will be performed. If you are interested in more information or testing, please make an appointment to consult with me at the Mount Sinai Doctors Faculty Practice.