Enviromental Allergen Avoidance


Maria Patricia S. Abes, MD; Maria Remedios D. Ignacio, MD; Nanneth T. Tiu, MD – a group of expert Filipino ALLERGISTS bond together as the H & L Allergy Team, whose aim is to give advice, to help readers understand and find relief in dealing with common allergic disorders.

For comments, questions or queries, please email: hl.famepublishing@gmail.com

Prevalence of asthma and allergies have steadily increased in the modern era. This has partly been attributed to increased exposure to indoor and outdoor environmental allergens. Common culprits include dust mite droppings, animal dander, cockroach droppings, pollens and molds.

The best defense against most allergies is to avoid the allergens that trigger your symptoms. Since complete avoidance is not always possible, there are things you can do to decrease your exposure.

Dust mites

Dust mites are microscopic 8-legged arthropods that have been recognized as the major source of allergens in house dust. They excrete numerous allergens that cause allergy in humans and can be found in carpets, beddings, upholstered furniture, and clothing but not on hard surfaces. Mites feed on organic materials such as skin scales, fungi, yeasts, and bacteria.

Dust mites require humidity to survive. Reducing humidity with air-conditioning or portable dehumidifiers at levels below 50 percent can minimize replication and below 35 percent can cause mites to become dormant.

If you have allergies triggered by mites, here are some tips on reducing mite allergen exposure:

• Mite-proof bedding covers for mattress, pillows, box spring can prevent exposure to mite allergen for individuals who sleep on them.
• Regular washing of bedding can reduce exposure to dust mite allergen. Washing in hot water is not required. Dust mites are killed by drowning rather than scalding.
• Regular and frequent (at least weekly) use of a high-efficiency vacuum cleaner can lead to sustained reductions of dust mite particles that have settled into carpeting, upholstered furniture and beddings.
• Remove reservoirs of mite allergens completely from the environment like carpets and drapes.


Pollen are tiny grains needed to fertilize many kinds of plants. Plants with colorful flowers, like roses, usually do not cause allergies. These plants rely on insects to transport the pollen for fertilization. Grasses, trees and weeds produce powdery pollens that are spread by the wind and are inhaled. These plants cause allergy symptoms. In warm places, pollination can be year-round.

If possible:

• Keep windows closed during pollen season, especially during the day.
• To avoid pollen, know which pollens you are sensitive to and then check pollen counts.
• Take a shower, wash your hair, and change clothing after working or playing outdoors.


There are no “hypoallergenic” breeds of dogs or cats. That is because people are not allergic to the hair of dogs and cats but to an allergen found in the saliva and dander (dead skin flakes). The source of allergens from rabbits, hamsters, mice and guinea pigs is the urine.

Pet allergy symptoms typically occur within minutes, with short-term exposure. With more chronic exposure symptoms may occur more chronically and not as acutely. For some people, symptoms build and become most severe 8 to 12 hours after contact with the animal.

If you have an allergy to animals, it’s best not to get a new pet. If you already have a pet you cannot live without, you should:

• Keep the pet outdoors or restrict it to a few rooms in the house. At the very least, keep the pet outside of the bedroom.
• Wash hands after petting.
• Regular vacuum cleaning is essential to prevent accumulation of allergens.
• Regular bathing of pets to remove allergens can be helpful. Wash a dog at least twice a week for the intervention to be effective. An indoor cat should be washed more frequently to reduce airborne cat allergens.
• Air filtration is effective if the allergens of concern are associated with air-borne particles that are consistently available.

Cockroaches and rodents

Integrated pest management involves:

• Preventing access – blocking means of ingress by aggressive caulking of the cracks or gaps around piping, crevices and windows.
• Killing or trapping pests using either targeted application of chemicals, or mechanical methods.
• Encasing Food Supplies – Food should be fully enclosed or kept in a refrigerator. No waste should be kept in the home, and dishes or pans should not be left out with any food debris on their surfaces.
• Cockroaches need water to survive, so fix and seal all leaky faucets and pipes.
• Once removed, deep and thorough cleaning can reduce residual allergens that have accumulated in reservoirs.


Molds are tiny fungi related to mushrooms but without stems, roots or leaves. Molds can be almost anywhere, including soil, plants and rotting wood. Their spores float in the air, much like pollen. Molds are found in outdoor air and can enter your home any time you open a door or window.

Indoor mold thrives in damp basements and closets, bathrooms, places where fresh food is stored, refrigerator drip trays, house plants, air conditioners, humidifiers, garbage pails, mattresses, upholstered furniture, and old foam rubber pillows. There are numerous allergen-producing genera that can grow indoors.

You can control mold in your home if you:

• Clean bathrooms, kitchens, and basements regularly and keep them well aired.
• Get rid of mold growth on hard surfaces with water, detergent and, if necessary, 5% bleach (do not mix with other cleaners). Then dry the area completely.
• Repair and seal leaking roofs or pipes.
• Using dehumidifiers in damp basements may be helpful, but empty the water and clean dehumidifier units regularly to prevent mildew from forming.
• Avoid carpeting on concrete or damp floors, and storing items in damp areas.

Environmental allergens can trigger symptoms in people with allergic asthma, rhinitis, and atopic dermatitis. With the help of your allergist, you can identify things in your home, workplace or school that make your symptoms worse. Environmental control practices if implemented properly may reduce your allergy symptoms..

• Environmental Trigger Avoidance, ACAAI
• Allergy Avoidance, World Allergy Organization
• Indoor Allergen / Outdoor Allergen, AAAAI
• Environmental assessment and exposure control of dust mites: a practice parameter, Annals of Allergy Asthma and Immunology

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