Dander is a common source of allergens in indoor air quality. It is defined as microscopic particles shed by animals that easily become airborne and circulate through living spaces. Dander often triggers allergic reactions, impacting respiratory health and comfort for many individuals. This article explains what dander is, how it affects health, why it persists in the environment, and how to manage it.
Defining Airborne Dander
Dander is a complex material carrying dried proteins that trigger allergic responses, not just pet hair or shed skin. While it includes minute flakes of dead skin cells, the true allergens are proteins found in the animal’s saliva, urine, and sebaceous glands. These proteins adhere to the fur and skin, flaking off into the air when the animal grooms or moves. All warm-blooded animals, including cats, dogs, rodents, and birds, produce dander. For example, cats produce the glycoprotein Fel d 1, and dogs produce Can f 1, both of which are potent allergens.
The Mechanism of Allergic Reaction
An allergic reaction begins when the immune system mistakenly identifies dander proteins as a threat. Upon initial exposure, the immune system produces Immunoglobulin E (IgE) antibodies, which bind to mast cells located in tissues like the respiratory tract. When the individual is exposed again, the dander binds to the IgE-coated mast cells, signaling them to release chemicals like histamine. This release causes common pet allergy symptoms, such as sneezing, runny nose, itchy eyes, and nasal congestion. For those with asthma, inhaling dander can cause a severe inflammatory response, resulting in wheezing, coughing, and difficulty breathing.
Environmental Factors and Persistence
The microscopic size of dander particles makes them difficult to control indoors. Pet dander typically measures between 2.5 and 10 microns, with many particles smaller than 2.5 microns. These lightweight particles can remain suspended in the air for extended periods, unlike heavier allergens that settle quickly. Air currents from normal household activity easily re-suspend settled dander back into the breathing zone. Dander is also spread throughout a building by HVAC systems and adheres readily to clothing and shoes, tracking into pet-free areas.
Strategies for Reduction
Reducing dander requires a multi-faceted approach focusing on the source, air quality, and surfaces.
Source Control
Source control involves regularly managing the pet, such as bathing the animal at least once a week to reduce allergen shedding. It is also beneficial to establish pet-free zones, especially the bedroom of any allergic individual, to maintain consistently lower allergen levels.
Air Quality Improvement
Improving air quality is accomplished through filtration using high-efficiency particulate air (HEPA) filters. HEPA air purifiers and vacuum cleaners capture particles as small as 0.3 microns, effectively removing microscopic dander from the air and surfaces. Replacing standard HVAC filters with those rated MERV 11 or higher can also help trap smaller particles before they circulate throughout the home.
Surface Cleaning
Regular surface cleaning is necessary for reducing dander accumulation. Frequent vacuuming of carpets and upholstery must be done with a HEPA-filtered vacuum to remove trapped particles. Washing bedding and other fabrics weekly in hot water, at least 130 degrees Fahrenheit, helps denature the allergenic proteins. Dusting surfaces with a damp cloth, rather than a dry one, ensures that tiny particles are captured instead of being redistributed into the air.