Researchers Divided on Toxic Mold

Last Editorial Review: 1/31/2005

Researchers are at odds as to how harmful some household molds truly are.

By Jean Lawrence
WebMD Feature

Reviewed By Brunilda Nazario

Several years ago, Cheryl, a special education assistant in Vancouver, British Columbia, said her son, then about 18 years old, started throwing up each morning. Yet when he was on the road with his band, he didn't throw up. Eventually, she and her husband peeked under their son's waterbed and gasped! Underneath, she says, was a solid coating of black slime with a fluorescent green cast, which turned out to be stachybotrys chartarum -- a controversial fungus suspected by some researchers of causing a gamut of illnesses in susceptible people.

But is the creeping, black slime a silent household health hazard or not?

"Let's just say two factions have developed," says Jay Portnoy, MD, a physician at Children of Mercy Hospital in Kansas City, Mo., and a fellow of the American Academy of Allergy, Asthma, and Immunology (AAAI). "Some doctors now say there is no evidence at all that it causes harm. Others say it may be causing a lot of symptoms. I come out in the middle. There seems to be a relationship between mold and illness, but it's hard to prove. We can't blow mold in people's faces to see what happens. That wouldn't be ethical."

"Mold is more of a transient annoyance," counters Emil J. Bardana, Jr., MD, professor of allergy and immunology at Oregon Health & Science University in Portland and also a member of the AAAI, counters: "House dust mites, animal dander, and cockroach allergens cause many more problems."

Nevertheless, Portnoy maintains that there is a growing body of evidence that penicillium and aspergillus, which are usually found indoors and smell bad, and cladosporium, present in outdoor air and less odoriferous, are not good to have around.

However, it is the green-black scourge stachybotrys that has gotten the most press, attacking the houses of high-profile victims such as crusader Erin Brockovich and resulting in crushing lawsuits that have driven up insurance rates and sent homeowner insurance companies into a tizzy. Stachybotrys, however, is associated with only 20% of reported cases of suspected mold exposure.

What Might Make You Suspect Toxic Mold

Portnoy says his interest was prompted by escalating numbers of asthma patients coming into his hospital. They sent inspectors to the homes of some kids with stubborn cases and found mold in high percentages. Sometimes the symptoms mimic asthma -- difficulty breathing and sneezing. Or existing asthma can be exacerbated, sometimes to a fatal level.

Other symptoms include fatigue, nausea, vomiting, and strange rashes. In one famous instance, in the mid-1990s, a cluster of 45 cases of lung bleeding in infants, 16 of whom died, was attributed to stachybotrys.

With respect to the latter, Bardana says, "This has been retracted."

"Changed," Portnoy shoots back, "not retracted."

The study's author, Dorr G. Dearborn, MD, PhD, professor of environmental sciences at Case Western Reserve University in Cleveland, says the Centers for Disease Control altered his epidemiological study design, which resulted in 1.5% chance of infant lung bleeding if exposed to stachybotrys, instead of the 9.8% reported earlier. Although a smaller number, this is still statistically significant, Dearborn insists.

How Toxic Mold Acts on the Body

According to Portnoy, mold attacks in one of four ways.

First, you could be allergic to it. This occurs in 10% to 20% of cases. A skin or blood test would pinpoint it as an allergic substance.

Second, substances called ergosterol and glucan in the walls of the mold cell can cause hay fever-like symptoms. You don't have to be allergic -- anyone could react to these.

Third, molds release organic compounds such as benzene and acetone, which would raise alarms in any workplace and are linked to nausea, dizziness, and headaches. Again, you don't have to be allergic.

And last, molds, like other organisms, don't want to compete for food and nurturing, so they expel mycotoxins to kill competitors such as bacteria. In the case of helpful mycotoxins, we call these antibiotics and use them to help us. But in the case of some molds, the mycotoxins target cells within our bodies and may cause problems such as cancer, stillbirths, and bleeding in infants. Stachybotrys makes a lot of these harmful mycotoxins.

"There is no literature that convinces me people get sick from inhaled mycotoxins. From eating them, yes," Bardana says. Other researchers have also found a dearth of "well substantiated, supportive evidence of serious illness due to stachybotrys exposure in a contemporary environment."

"You can always say there isn't enough evidence," Portnoy says. "What's enough evidence? Whatever these people say it is."

Where Toxic Mold Hides

If you consider mold a potential problem, you should know it we are not talking about green bread mold or the kind that grows on shower tiles. Potentially toxic mold grows on wood, fiber, or paper that has gotten wet for more than a few days. Growth occurs when there is moisture from water damage, excessive humidity, water leaks, water infiltration, or even from flooding.

The U.S. Environmental Protection Agency reports that the tiny mold spores waft through the air and land on inviting damp spots. The spores may enter your home through the ventilation systems, doorways and windows and are distributed around the house. The only way to get rid of the mold permanently is to get rid of the moisture. You can do this by:

  • Fix leaks and seepage, even if it involves landscaping around basements.
  • Put plastic over dirt in crawlspaces and keep them well ventilated.
  • Use exhaust fans in kitchen and bathroom.
  • Turn off humidifiers if you see condensation on windows.
  • Use dehumidifiers and air conditioners, especially in hot humid climates.

Also, pay special attention to carpet on concrete floors. Use area rugs that can be lifted and washed, or install a vapor barrier over the concrete.

Even Bardana recommends cleaning up mold if you find it. "Don't go crazy, don't burn your house down," he adds. "This debate is so overheated." In most cases cleaning with bleach and water can remove mold, but for more extensive problems contact a professional with experience cleaning mold can be contracted.

Star Lawrence is a medical writer based in the Phoenix area.

Published Sept. 15, 2003.

SOURCES: Jay Portnoy, MD, Children of Mercy Hospital, Kansas City. Mo. Emil J. Bardana, Jr., MD, professor, allergy and immunology, Oregon Health & Science University, Portland, Ore. Dorr G. Dearborn, MD, PhD, professor, environmental sciences, Case Western Reserve University, Cleveland. Bardana, E. "Indoor Air Quality and Health," Journal of Clinical Allergy and Immunolgy, May 2003; vol 23: pp 291-309. Environmental Protection Agency.

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