Controlling Your Home Environment to Prevent Asthma Flares

Dust Mites

Dust mites thrive when there is enough to eat (human skin flakes), and the air is moist and warm. Their droppings trigger allergy reactions in allergic children.

To limit the dust mites in your home:

  • Cover pillows, mattress, and box spring in allergen-proof casings. These keep the mites inside.
  • If a comforter is used, cover it with an allergen-proof cover to keep the mites out.
  • Wash bed sheets and pillow cases once a week in hot water (130 F).
  • Clean blankets monthly.
  • Put items that can't be washed in high heat (in the dryer at 130 F for 20 minutes) or extreme cold ( the freezer -1 to -4 F) overnight once per month. Drying or freezing can kill mites and remove the droppings, though washing things is still preferable.
  • Avoid sleeping on floors or upholstered furniture.
  • Keep your home at an optical humidity level, which is less that 50%. Use a dehumidifier with adequate capacity (at least 40 pints) and keep the air as cool as possible, too.
  • Hardwood or other easily cleaned flooring and washable area rugs are the best choices for allergy sufferers.
  • If installing carpet, choose low pile.
  • When vacuuming carpet or upholstered furniture, use a HEPA filter in the vacuum or use a 2-ply vacuum bag.
  • Vacuum weekly and stay out of the room for 30 minutes after vacuuming. Use a damp cloth to dust.
  • Do not sweep with a broom in the bedroom as this will stir up dust. It will not be collected.
  • Avoid clutter, especially on the bed and floor.
  • Use blinds or curtains that can be washed.

We can measure dust mite allergen content in dust samples to assess your and your family's risk.

Animal Dander

The dead skin cells of warm-blooded animals (such as cats, dogs, mice, and birds) is known as animal dander. This dander can cause asthma symptoms and trigger allergic reactions in children. Non-allergenic cats and dogs do not exist and even hairless pets can cause allergic reactions. And once you are sensitized to animal dander, there is no evidence that you can grow out of it.

Removal of the animal from the home is the most effective control measure. Then you should:

  • Remove rugs from the home, as cleaning is less effective.
  • Clean furniture
  • Wash walls and have them repainted.
  • Remove carpets in the bedroom if possible.

If an animal does remain at home:

  • It's best if the pet lives outside, or in an isolated area.
  • Wash your pet weekly. This may temporarily decrease the amount of allergen on the pet, but washing will not be very helpful to reduce symptoms.
  • Pets should not be in the car with an allergic person for extended periods.
  • Wash hands after direct contact with your pet.
  • Pets should never be allowed in the bedroom, especially not on the bed.
  • Avoid facial contact with animals and contact with the pet's toys.
  • Use an air cleaner with a HEPA filter in the bedroom and living room, or in the room where your child spends the most time. The air cleaner works best if there are no rugs.
  • Cover pillows, mattresses, and box springs in allergen-proof casings.
  • Change clothes and take a bath or shower after visiting a home with an animal.
  • If your child has eczema, bathe the child before bed and do not allow contact with the pet before the child goes to sleep.

Even after animal removal and thorough cleaning, it may take 6-12 months for allergen levels to fall to a point where symptoms improve. 


Molds are microscopic fungi; their spores float in the air like pollen. Molds thrive in damp areas with decaying materials. There are many molds, the most common being Alternaria and Cladosporium.

Outdoor mold spores begin to appear after a spring thaw and peak in July through October. These molds can be found in soil, leaves on the ground and rotting wood.

Indoor molds (mildew) may be found in basements, bathrooms, refrigerators, garbage containers, houseplant soil, carpets, upholstery and even Christmas trees.

To limit your child's contact with mold:

  • Avoid damp and dusty places such as attics and basements.
  • Regularly clean and ventilate basements, bathrooms and kitchens.
  • Use a dehumidifier with adequate capacity (at least 40 pints) to keep a basement dry. Empty collected water often, or drain.
  • Clean cool mist vaporizers weekly. Inspect air conditioner filters weekly.
  • Keep houseplants to a minimum and out of the bedroom.
  • Use window air conditioners with the vent to the outside closed.
  • Do not use carpeting in damp areas.
  • Repair leaks in your roof, walls, and windows.
  • Vent the clothes dryer to the outside.
  • Keep windows closed, as outdoor molds can blow into the home through open windows and doors.
  • Don't stir up piles of leaves during the fall season, as this releases mold and pollens.


Roaches thrive in areas with food and moisture and elimination may be very difficult. To keep them out of your home:

  • Exterminate/fumigate (professional), then thoroughly clean. Add bleach to the wash water.
  • Keep the stove and all kitchen areas clean, dry and free of food particles.
  • Keep the house dry. Allow sinks, tubs, and floors to dry every day. Remove sources of standing water.
  • Keep food tightly sealed and all surfaces clean.
  • Use strategically place roach baits.
  • Vacuum and wet wash home thoroughly.
  • Place trash outside nightly.
  • Seal all cracks.

Cigarette Smoke and Airborne Irritants

Exposure to tobacco smoke has been proven over and over to worsen asthma in all ages, even if exposure is only second hand. Other airborne irritants can have a similar effect. To limit his exposure to these allergens, your child should:

  • Avoid being in confined areas with smokers: riding in cars, public places, at home.
  • Avoid spraying insecticides or other strong smelling products in the house.
  • Avoid smoke from fireplaces and wood burning stoves.
  • Avoid strong cooking orders, especially from frying.
  • Limit physical activity during periods of high air pollution or ozone alert days.
  • Use an adequate air filtration system with a HEPA filter.
  • Avoid painting in enclosed areas and spending extended periods of time in freshly painted areas.
  • Not use spray room deodorizers or dust sprays in the bedroom.


To lower your child's exposure to pollen, both indoors and out:

  • Use air conditioners, which filter our pollens and allow you to close your windows. Close the outside vent on window-type air conditioners to get the best protection.
  • Do not use window or ceiling fans, especially with the windows open.
  • Don't hand clothing outdoors to dry.
  • Keep in mind that the pollen count is highest in the morning. Limit time outdoors between 5 and 10 am and on hot, dry, windy days when the pollen and mold counts are highest.
  • Wear a face mask if outdoor activity cannot be avoided during peak seasons. If possible, do not hang clothes to dry.


It's important to hire a professional to exterminate your home, then thoroughly clean it. Once rodents have been removed, keep food in tightly sealed containers and seal all cracks to keep them out.

Reviewed by: Allergy Section
Date: February 2009