Indoor Allergies

House dust often contains a mixture of tiny particles that commonly cause allergic symptoms. These include dust mites, cockroaches, fungi spores (mold) and animal dander.


Dust mites are so tiny that they cannot be seen with the naked eye (microscopic). They are relatives of the spider. They live on mattresses, pillows, bedding, upholstered furniture, carpets and curtains. These tiny creatures feed on skin flakes that people and pets shed daily. They commonly float around in the dust in your home when vacuuming or when bedding is disturbed. The air-born dust mites often cause runny noses and symptoms of asthma. The problems are similar to a pollen allergy.

These mites thrive in summer and die in winter. In a warm, humid house, however, they continue to thrive even in the coldest months. The particles seen floating in a shaft of sunlight include dead dust mites and their waste-products. These waste-products, which are proteins, cause the allergic reaction. Even in the cleanest home, dust mites still exist. This is because typical cleaning methods cannot eliminate many of the dust particles.


Cockroach allergy is primarily caused by their droppings. It is found in house dust, especially in older homes.


Mold is very often found in homes and house dust, and when in high concentrations may become harmful, especially for people allergic to mold. They tend to grow faster in the presence of moisture.


Pets (furred animals) can cause allergies too. This is not caused by the fur, but from the proteins in their skin, saliva and urine. These proteins are called allergens. The dander (skin scales) is the source of most pet allergies. Therefore, short-haired animals can cause allergies as much as long-haired animals. Dander and saliva are the source of cat and dog allergens. Urine is the source of allergens from rabbits, hamsters, mice and guinea pigs.


Dust mites

  • Use a dehumidifier or air conditioner to keep the humidity low (50% or below).

  • Cover your mattress and pillows in dust-proof or allergen resistant covers.

  • Wash all bedding and blankets once a week in hot water (at least 130 - 140°F). Non-washable bedding can be frozen overnight to kill dust mites.

  • Replace wool or feathered bedding with synthetic materials and traditional stuffed animals with washable ones.

  • If possible, replace wall-to-wall carpets in bedrooms with bare floors (linoleum, tile or wood). Remove fabric curtains and upholstered furniture.

  • Use a damp mop or rag to remove dust. Do not use a dry cloth since this stirs up mite allergens.

  • Use a vacuum cleaner with either a double-layered micro filter bag or a HEPA filter. These filters trap allergens that pass through a vacuum's exhaust.

  • Wear a mask while vacuuming to avoid inhaling allergens. Stay out of the vacuumed area for 20 minutes while dust and allergens settle.

  • Use only high efficiency media filters for your furnace and air-conditioning, preferably with a MERV rating of 11 or 12. In order to maintain a clean filter, remember to change it at least every three months.


  • Control cockroaches by eliminating their entrance to the home and by eliminating their food sources.

  • Block crevices and cracks and remove water sources such as leaky faucets and pipes.

  • Keep food out of the open when finished eating. This also includes pet food. Sealed containers for food work well. Remove crumbs that may have accumulated such as in a toaster.

  • Use garbage containers that have lids and immediately clean off counters, tables and stove tops.

  • An exterminator might be helpful as well.


  • Control mold by eliminating moisture and dampness.

  • Repair leaks around the home including the roof and pipes.

  • For high humid areas consider using dehumidifiers. Rooms with the most moisture include kitchens, bathrooms and basements.

  • Ventilation and cleaning are also important.

  • Detergent or 5% bleach can be used to clean off mold from hard surfaces. It is important not to mix bleach with other products and to dry the area completely after cleaning.

  • For more extensive mold problems hire an indoor environmental professional.

  • For mold on clothing, soap and water work best. If they cannot be cleaned throw them out.

Animal dander

  • Control pet dander by removing pets from your home. If this is not an option then try lessen the contact by keeping the pet out of areas that you spend most of your time, such as the bedroom.

  • Vacuum often and consider replacing carpet with a hardwood floor, tile or linoleum.

  • A HEPA air cleaner may also help to reduce the level of animal allergen in the air.