Unexpected Pet Hair

Dr. Greene’s take on pet hair…

Dog and cat allergens are found in almost all US homes, whether or not dogs or cats live there. The highest concentrations are found on sofas, especially upholstered sofas. The National Institute of Environmental Health Sciences and the US Department of Housing and Urban Development conducted a national survey to measure levels of indoor allergens that might trigger asthma. The surprising results were published in the July 2004 Journal of Allergy and Clinical Immunology.

Dog allergen was detected in 100 percent of homes, and cat allergen was detected in 99.9 percent of homes, even though most households don’t own a dog or cat. In homes with dogs and cats, the levels of allergens are almost always high enough that they could possibly trigger allergies or asthma. Even 36 percent of homes without dogs had dog dander levels high enough to provoke symptoms. And 16 percent of homes without a cat had similarly high levels of cat dander. Where does this come from? Presumably it is tracked into the home on clothes, and rubs off where people commonly sit. It also gets into the air. HEPA air filters can reduce exposure levels, perhaps below the symptom threshold.