Indoor allergens during the winter

January 3rd, 2012

Although many pollen-allergic individuals may experience less allergy/asthma symptoms this time of the year, others may “peak” with symptoms and medication requirement. Indoor allergens (house dust mite, mold, animal danders) are often the cause of symptoms during late fall, winter, and early spring.
Environmental allergen exposure studies suggest that even when a pet is only intermittently indoors, dander levels are well above the symptom threshold for cat and dog allergens when the pet is not physically present. Such studies suggest that the dog who is confined only to the laundry room at night or the cat that never enters the bedroom will likely cause symptoms in sensitized individuals regardless of location.
House dust mite and indoor mold allergens are ubiquitous in westernized society (except at very high elevation… think Denver), though older and less-maintained homes certainly represent greater sources of exposure. In principle, sensitized individuals better tolerate indoor living when occupants regularly clean, implement appropriate dust mite reduction strategies, and maintain HVAC or other air filtration systems per manufacturer guidelines. Select studies have also demonstrated improvement in allergen levels using HEPA filtration systems in living areas. However, even heroic cleaning and maintenance programs often do not bring dust, mold, or animal dander levels below the symptom threshold for many people who have indoor allergies. Medical treatment and/or immunotherapy are excellent and proven options for such people.
Kevin Parks MD