Is Household Mold Worsening Your Asthma?

Mold is a microscopic fungus that thrives in damp dark conditions. It can grow on any surface (e.g., food, indoor plants, walls, floors, or fabric) under the right condition—moisture and high humidity, plus some form of nutrient.

Mold also is a common indoor trigger for asthma symptoms, among them:

If you have asthma and you're sensitive to mold, reducing your exposure to it should be an effective way to stave off asthma symptoms.

Signs of Mold in Your Home

There are a number of clues you may have mold in your home:

  • White, orange, green, or black growth in a moist area
  • A musty, mold odor
  • Discoloration in a wall, ceiling, or area with prior water damage
Mold growth. Mould spores thrive on moisture. Mold spores can quickly grow into colonies when exposed to water
Fevziie Ryman / Getty Images

Prevent Mold Growth in Your Home

Decreasing your mold exposure will require both the removal of mold and moisture control. There are a number of things you can do to prevent mold growth in your home:

  • Wash, disinfect, and dry all surfaces.
  • Don't let water build up anywhere.
  • Repair any leaks and dry moisture that results from leaks both inside and outside your home.
  • Ventilate, preferably to the outside of your home with exhaust fans, the source of any moisture such as clothes dryers, stoves, and other appliances.
  • Put plastic over any dirt crawl spaces and make sure the crawl spaces are well ventilated.
  • Limit the number of indoor plants in your home.
  • Maintain a relative humidity of at less than 50%; this may require air conditioning or a dehumidifier.
  • Keep drip pans from appliances such as refrigerators and air conditioners clean and dry.
  • Install an air filtration system or air purifiers, such as one with a high-efficiency particulate air (HEPA) filter, to remove mold and other particulates such as dust, pollen, and bacteria, from the air.

What to Do If You Find Mold Growth in Your Home

If you have asthma, exposure to mold creates serious health risks. If you notice mold in your home, do not attempt to take remove it yourself. Most serious mold problems should be mitigated by a professional.

  • Figure out where the moisture is coming from and fix that problem first. Remember, you may not always see mold—think mold if you enter a room and smell musty, stale air. Also, note that mold can be hidden by wallpaper or tile.
  • The most likely areas are those with high humidity and moisture such as the kitchen, bathroom, or basement.
  • Check rooms with water sources, as leaky pipes in walls are another common place for mold to accumulate.
  • Scrub mold off from affected areas with detergent and water, clean the area, and then let dry completely.
  • Certain materials tend to hold moisture and may need to be replaced, among them sheetrock, ceiling tiles, and carpet.
  • While you can easily clean a little mold off the bathroom area, you may want to consider a professional cleanup for anything over 10 square feet.
  • Make sure any areas you are working in are well ventilated or you may increase your acute exposure to molds.
  • Use an air conditioner during the most humid months.
  • Avoid carpet in areas like bathrooms.
  • Consider using paint that is "mold-resistant."
  • While the trend in home building and remodeling is to make housing "airtight" in order to make them more energy-efficient, older houses that "breathe" more are less likely to harbor mold.

For mold mitigation to be effective, it's important to take a "multicomponent" approach, according to recommendations for asthma management issued by the National Institutes of Health (NIH) in December 2020. In other words, simply removing moldy carpet, say, or installing an air filter will not be sufficient.

For example, the NIH suggests "three single-component interventions (eg, air purifiers, impermeable pillow and mattress covers, and HEPA vacuum cleaners) for individuals sensitized and exposed to dust mites and mold."

Your doctor can help you determine which measures will be most useful to you and others in your household with asthma who are sensitive to mold.

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Article Sources
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  1. Cloutier MM, Baptist AP, Blake KV, et al. 2020 focused updates to the asthma management guidelines: A report from the national asthma education and prevention program coordinating committee expert panel working group. Journal of Allergy and Clinical Immunology. 2020;146(6):1217-1270. doi:10.1016/j.jaci.2020.10.003

Additional Reading
  • Indoor Environmental Asthma Triggers. Environmental Protection Agency. 
  • National Heart, Lung, and Blood Institute. Expert Panel Report 3 (EPR3): Guidelines for the Diagnosis and Management of Asthma