Allergens are substances that commonly cause allergic reactions. Some allergens are animal dander, pollens, house dust mites, molds, and rarely some foods. Contact with these substances can cause a chemical reaction to take place in the body which can trigger asthma. It is important to remember that allergens can trigger asthma only in children with irritable airways. Allergy testing, a detailed medical history, and careful examination of the environment can help identify allergic triggers. When allergens such as animal dander trigger your child’s asthma, the best treatment is simply to remove the animal from the household. An asthmatic child should not hold an animal they are allergic to since the allergen can cling to skin and clothes. Washing the hands well after handling a pet can remove allergens from the hands.

House Dust

The dust mite is the major allergy-causing substance in house dust. Dust mites are microscopic insect-like creatures that live in carpets, mattresses, and upholstered furniture. They thrive in warm humid conditions. Their diet is shed scales from human skin. Dust mites produce waste particles that become part of house dust. When an allergic person inhales these particles, they can experience reactions such as nasal congestion and asthma symptoms.

What you can do to control dust mites in your home

There are several things you can do to decrease the levels of allergy-causing dust mites in your home. The areas you will need to pay special attention to are the living room or family room where the allergic person(s) spends a lot of time and the bedroom where he/she sleeps. Here are the steps to take:

Primary objectives:

  • Place zippered, dustproof covers over pillows, mattress and box springs*
  • Wash bedding (sheets, blanket, etc.) in hot (130 degrees) water weekly
  • Avoid lying or sleeping on carpet or upholstered furniture
  • Vacuum when the allergic person is not present (they should be out of the house for 20 minutes after vacuuming)
  • Use a vacuum cleaner with high allergen containment

Secondary objectives:

  • Use wipeable wooden, leather or plastic furniture instead of upholstered furniture
  • Remove, wash or freeze stuffed toys (freeze for 72 hours)
  • Remove the carpet from the bedroom or area in which an allergic patient lays

Steps to consider:

  • Air conditioners can be used to keep humidity low (30-50%)

*Pillow and mattress covers should totally encase the pillow or mattress and zip closed. They should be designed specifically to prevent the passage of allergens through the weave or seams of the cover. Allergy proof covers vary in design with some offering a cloth outer cover for greater comfort. The important point is that the mattress be encased and that the cover be sealed


Molds are microscopic fungi that are among the most widespread living organisms. Molds prefer warmth and humidity and can be found year-round if these conditions are present. They are common outdoors in shady, damp areas such as on decaying leaves and in moist areas in homes such as showers and basements. There are thousands of different varieties and some release spores into the air which, when inhaled, can cause allergic reactions such as asthma symptoms.

What you can do to decrease mold exposure


  • Avoid exposure to areas of high mold growth
  • Wear a mask if exposure can’t be avoided
  • Allow adequate ventilation in the house
  • Clean walls and ceilings and add mold inhibitor to paint before applying
  • Limit houseplants that harbor molds
  • Store firewood outside
  • Avoid live Christmas trees
  • Follow steps to reduce dust exposure
  • Avoid foam rubber mattress and pillow
  • Use an exhaust fan or window to remove bathroom humidity when bathing
  • Wash bathroom fixtures, floors, and tiles with a mold-killing solution
  • Do not use bathroom carpet
  • Clean refrigerator and garbage cans with mold-killing solution
  • Dry clothes immediately after washing
  • Vent clothes dryer to the outside
  • Avoid carpet over concrete floors


  • Avoid cutting grass or raking leaves around mold-allergic individuals
  • If an allergic person cannot avoid mold exposure, they should wear a face mask
  • Avoid soil, compost piles, sandboxes, hay, fertilizers, and barns
  • Prune trees to avoid shading of the home
  • Avoid pooled water near home
  • Avoid camping or walking in the woods where mold growth is high

Steps to consider:

  • Electrostatic filters overheating/cooling vents can remove airborne mold spores
  • Air conditioners can be used to keep humidity low (less than 40% is ideal)


Cat allergen, the allergy-causing substance from cats, is a protein present in the dander and saliva of cats. There is no such thing as a non-allergenic breed of cat. Even when a cat is no longer in the home, it can take as long as 20 weeks for cat allergen to decrease to levels found in homes with no cats. When these allergens become airborne, they can be inhaled and cause allergic reactions such as nasal congestion, itching around the eyes, or asthma symptoms.

What you can do to reduce exposure to cat allergen

Clearly, the most effective way to reduce exposure to cat allergen is to remove cats from the environment. However, if that is not an option there are some things you can do to decrease exposure.

  • The cat must be kept totally out of the allergic person’s bedroom
  • Remove bedroom carpet…if that is not possible it should be vacuumed thoroughly
  • Encase pillows and mattress
  • Use wipeable furniture such as plastic, wood or leather
  • Ventilate the house with exhaust fans and open windows
  • Vent filters will help prevent allergen from blowing throughout the house
  • HEPA air cleaners may help decrease airborne allergen
  • Clean walls
  • Keep the cat outdoors as much as possible
  • Wash the cat every few weeks
  • Wash hands and change clothes after handling the cat
  • Vacuum when the allergic person is not present
  • Use a vacuum cleaner with high allergen containment

Other Exposures

Paint cans

Greenhouses, antique shops, saunas, sleeping bags, summer cottages and hotel rooms, farming, gardening, baking, florists, carpenters, mill workers, upholsterers, and paperhangers.

Here are some more ways to reduce exposure to household allergens if the allergy testing shows the child has household allergies:

  • Remove scatter rugs, stuffed animals, and feather pillows
  • Use washable blankets, pillows, and curtains
  • Clean the house often (especially carpets, draperies, bedding, and upholstered furniture). Clean when the child is not home to breathe the things stirred up by cleaning
  • Change or wash air filters on furnaces and air conditioners at least monthly
  • If your child is sensitive to dust mites, talk to your doctor about using special chemicals that can kill dust mites in rugs and mattresses
  • Avoid contact with pets
  • Avoid smoke
  • Avoid fumes from paint, chemicals, cleaners, or gasoline
  • Keep the humidity down in your house if you can

Do not hastily undertake major changes to your home unless you are sure this will help.