What Is a House Dust Allergy?
Some people start to sneeze or cough, get wet and itchy eyes or even symptoms of asthma (wheezing, cough, short breath, chest tightness) during vacuuming, dust cleaning, changing beds, shopping, or other activities where dust appears in the air.
Mechanism of house dust allergy. Some substances, like parts of dust mites or mold spores, when inhaled, trigger production of immunoglobulin E (IgE) antibodies in a sensitive person. On subsequent dust exposures, antibodies bind to mast cells in mucosa in eye conjunctiva, nose, throat, and bronchi, and trigger release of histamine from them. Histamine causes dilation of vessels in mucosa, and secretion of mucus from mucous glands, resulting in mucosal swelling and mucus secretion.
Even small amount of dust in thoroughly cleaned homes may be enough to cause allergy so dust allergies do not appear only in “dirty houses”.
Causes of House Dust Allergy
Main allergens (substances causing allergic reaction in sensitive people) found in the house dust are particles from:
1. House Dust Mites
House dust mites (Picture 1), about half a millimeter sized organisms, can be found on carpets, under beds, on bed lining, mattresses and pillows, armchairs and sofas. Sensitive persons get allergy to body particles of mites usually after they are inhaled.
Picture 1. Dust mite, as seen under the microscope
Cockroaches (check types of cockroaches with pictures), about 1-3 cm (0,5-1,2 inch) sized insects (Picture 2), live in hot humid climates all around the world; in houses they are mainly found in kitchens and bedrooms. Sensitive persons (those with asthma or other chronic allergy) may develop a skin rash (urticaria), itchy throat or, in severe cases, an asthmatic attack, when they come in contact or inhale cockroach feces or parts of their body. Prevention is in keeping the house dry and disposing any food remnants and garbage out from the house.
Picture 1. American cockroach (source: Wikipedia)
3. Indoor Mold Allergy
Spores are inactive forms of molds. They come into the house through windows, mainly from outdoor plants. They appear as microscopic particles in the house dust even if no molds can be found on the walls in the house. When spores land on the moist walls, carpets, or furniture or in wet places like bathrooms and basements, new molds may start to grow. In sensitive people they usually cause symptoms of rhinitis (sneezing, eye itching) after inhalation.
Molds may be irritating to some people because of their strong odor but this is not an allergy.
4. Indoor Animals (Pets)
Cats and dogs, or any other indoor warm blooded animal like guinea pigs or birds or even mice may shed allergens with skin particles and hair but also with saliva and urine. Pet owners may carry these allergens on their clothes and transfer them to their work places and schools. There are no non-allergenic cats or dogs.
Pollens from outdoor plants come into houses through open windows. Pollens from indoor plants may also cause allergy.
Diagnosis of a Dust Allergy
Diagnosis of dust allergy can be done by certified allergist or immunologist. Blood test may reveal raised eosinophils (a sub-type of white blood cells) and IgE antibodies. These findings usually only tell that a person may have an allergy but to find an exact cause tests with injecting suspicious substances under the skin (skin prick test) or placing patches with an allergen onto the skin (skin patch test) and then evaluating eventual skin reaction is needed.
Treatment of Dust Allergies
To the date, allergy as a disease can’t be treated but symptoms of allergic reaction can be limited by taking antihistamine medication by mouth soon after symptoms appear.
Allergic reaction in house dust allergy is rarely life threatening but it may be quite severe in persons with asthma and sometimes requires injection of adrenalin (epinephrine) into a muscle (personal epi-pens for self injection exist).
Prevention of House Dust Allergies
If you or your family member has a house dust allergy:
- Don’t have pets, plush toys, dry flowers, heavy carpets, wool bedding, or upholstered furniture in the house. Clean floors , carpets, and mattresses using vacuum cleaner with HEPA filter thoroughly once a week rather than every day, since dust remains in the air for up to 2 hours after cleaning. Use protective mask when cleaning, or don’t participate in cleaning at all. Use mite-proof covers on mattresses and pillows.
- Avoid situations where dust is likely to float in the air.
- Do not have uncovered food in the house and dispose food waste from the house regularly. Food attracts mice and cockroaches.
- Keep the home dry (below 55% humidity) to prevent thriving of dust mites.
- Children with an allergy to dust mites should not sleep close to the floor.
Do Down and Feather Cause House Dust Allergy?
ANSWER by EDFA (European Down and Feather Association): Feather and down do not cause allergy, and do not attract house dust mites.
- House dust allergy (acaai.org)
Article reviewed by Dr. Greg. Last updated on April 12, 2011