Mold in the home: Identifying and treating the issue to prevent health problems

Mold is a type of fungus, a group of organisms that also includes yeasts and mushrooms. Mold thrives in wet places. Outdoors, it forms on damp surfaces like rotting logs or wet leaves. Inside, it can grow in damp areas like bathrooms, basements, or kitchens. If your home has experienced a flood or you have leaky pipes, your house is more likely to develop mold.

Mold in your home can cause health problems. Here's a look at symptoms of mold exposure, and how to identify, treat, and prevent it.

Symptoms of mold exposure

Most molds aren't harmful, reassures Dr. Nicholas Nassikas, assistant professor of medicine at Harvard Medical School. In fact, some molds are even used to make foods like cheese and yogurt, or medications like penicillin.

But some people develop symptoms such as a runny nose, itchy eyes, and coughing after exposure. "Mold exposure can cause inflammation anywhere along the respiratory tract," Dr. Nassikas explains. If you have mold allergies or asthma, you may have an even more severe reaction, he adds.

Health risks of prolonged exposure to indoor mold

For those who are allergic, symptoms such as itchy, runny nose, coughing, and even wheezing can occur when outdoor mold levels are high, or if you're exposed to indoor mold, even for a short period of time.

Chronic exposure to indoor mold can cause additional, sometimes severe health complications, says Dr. Nassikas. These include:

Asthma. Childhood exposure to household mold raises the risk of developing asthma, according to a study published in the International Journal of Hygiene and Environmental Health. When researchers looked at over 40,000 children in the U.S., they found that almost 11% of those in homes where they were exposed to mold had asthma, compared to 7% of kids who were not exposed to mold in their homes.

Mood changes. A review of 19 studies published in Environmental Health Perspectives found that prolonged exposure to mold increased stress, depression, and anxiety in both adults and children.

Immune system changes.Research suggests that chronic exposure to indoor mold is associated with elevated levels of chemicals in the body, like C-reactive protein (CRP), that signify the presence of inflammation.

Black mold

Black mold is one of several different types of mold. There are even many different types of black mold. But when people talk about black mold, they're usually referring to Stachybotrys chartarum, or S. chartarum. (Stachybotrys chartarum was previously known as Stachybotrys atra.) This type of mold grows and spreads on materials that contain cellulose, like paper, wood, and drywall.

S. chartarum made headlines in the 1990s, when research suggested an association between black mold and lung hemorrhage in infants. "The link is controversial - it's not clear that S. chartarum was the cause," stresses Dr. Nassikas.

Even though black mold symptoms have gotten a lot of attention, black mold itself doesn't seem more dangerous than other types, adds Dr. Nassikas. "Prolonged exposure to any type of indoor mold may cause problems like asthma, lung inflammation, and cognitive and mood issues," he says.

How to identify mold

If you have mold, it's often obvious. "You'll usually see it, or smell it," says Dr. Nassikas. Look for fuzzy, discolored, or slimy patches in areas where there's a lot of moisture, like your bathroom, window moldings, your refrigerator door seal, or around air conditioners. Another tip-off is a musky odor, adds Dr. Nassikas. If you can't identify where it comes from right away, look behind and underneath surfaces like carpets, wallpaper, cabinets, and walls.

You may have heard of mold test kits, but the CDC doesn't routinely recommend them. The best thing to do is remove any mold if you see or smell it.

Common causes of mold growth in homes

"The number one cause of mold growth is water damage," says Dr. Nassikas. "If you see water, chances are there's mold there as well." Some common ways this can happen include:

• roof leaks
• excessive moisture in the bathroom
• high room humidity
• leaking water pipes
• water pooling near the foundation of your home.

Mold remediation: When to call a professional for mold removal

If you think you have mold, the first step is to call a professional to solve the underlying problem, says Dr. Nassikas. If you have mold from a leaky pipe, for example, you'll want to have a plumber come to fix it.

If the moldy area is smaller than a three-foot-by-three-foot patch, you can get rid of the mold yourself. The CDC recommends the following: Use soap and water, or a bleach solution with one cup of laundry bleach mixed with one gallon of water to scrub mold off hard surfaces. Dry completely. Open all the windows and doors for good ventilation, and wear rubber boots, gloves, and goggles while cleaning. You may need to throw away absorbent or porous materials like carpets or ceiling tiles, which cannot be thoroughly cleaned.

If the area is larger than about 10 square feet, or if you've had a major flood in your home, it's best to bring in professional mold remediation. Look for a mold removal company or professional who is certified by any of the following:

• National Environmental Health Association (NEHA)
• American Industrial Hygiene Association (AIHA)
• Institute of Inspection, Cleaning and Restoration Certification (IICRC)
• American Council for Accredited Certification (ACAC).

Your state may also be able to provide names of professionals in your area.

Preventing mold growth in the home

The best way to prevent indoor mold growth is to clean up and fix any water damage as soon as possible. If you see condensation or wet spots on walls, call a plumber who can help you find the source of the hidden leak. Other things you can do:

Regulate humidity levels in your home. If you regularly see condensation on your windows, it may be a sign that your home has high humidity levels. You can buy a hygrometer at your local hardware store to measure humidity in your home. If it's above 60%, use dehumidifiers. Ideally, you want to keep indoor humidity between 30% and 50%.

Run exhaust fans. Run the bathroom fan when you shower to prevent excess moisture. If you don't have an exhaust fan, open the window instead. Cooking can also raise humidity levels. Use your stove's exhaust hood to draw moisture out of the kitchen. If you have a clothes dryer, make sure it's vented to the outdoors.

Install outdoor drainpipes. These will help to get water away from the foundation of your house when it rains.