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Allergies, asthma, and molds

Allergic rhinitis - mold


Things that make allergies or asthma worse are called triggers. Mold is a common trigger. When your asthma or allergies become worse due to mold, you are said to have a mold allergy.

There are many types of mold. They all need water or moisture to grow.

  • Molds send out tiny spores that you cannot see with the naked eye. These spores float through the air, outdoors and indoors.
  • Mold can begin growing indoors when the spores land on wet surfaces. Mold commonly grows in basements, bathrooms, and laundry rooms.

Controlling mold indoors

Fabrics, carpets, stuffed animals, books, and wallpaper can contain mold spores if they are in damp places. Outdoors, mold lives in the soil, on compost, and on plants that are damp. Keeping your house and yard drier will help control mold growth.

Central heating and air-conditioning systems can help control mold.

  • Change furnace and air conditioner filters often.
  • Use high efficiency particulate air (HEPA) filters to best remove mold from the air.

In the bathroom:

  • Use an exhaust fan when you shower or take baths.
  • Use a squeegee to wipe water off shower and tub walls after you bathe.
  • Do not leave damp clothes or towels in a basket or hamper.
  • Clean or replace shower curtains when you see mold on them.

In the basement:

  • Check your basement for moisture and mold.
  • Use a dehumidifier to keep the air drier. Keeping indoor moisture levels (humidity) at less than 30 to 50% will keep mold spores down.
  • Empty dehumidifiers daily and clean them often with a vinegar solution.

In the rest of the house:

  • Fix leaky faucets and pipes.
  • Keep all sinks and tubs dry and clean.
  • Empty and wash the refrigerator tray that collects water from the freezer defroster often.
  • Frequently clean any surfaces where mold grows in your house.
  • Do not use vaporizers for an extended time to manage symptoms during asthma attacks.


  • Get rid of water that collects around the outside of your house.
  • Stay away from barns, hay, and wood piles.
  • Do not rake leaves or mow grass.


Platts-Mills TAE. Indoor allergens. In: Adkinson NF Jr., Bochner BS, Burks AW, et al., eds. Middleton's Allergy Principles and Practice. 8th ed. Philadelphia, PA: Elsevier Mosby; 2013:chap 28.

Reisacher WR. Allergy treatment: environmental control strategies. Otolaryngol Clin N Am

Update Date 5/18/2014

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