People suffering from toxic mold syndrome (search) — often blamed on a kind of black mold that grows on damp indoor surfaces — likely have more ordinary illnesses, a new study shows.

The finding comes from a hard look at 135 patients referred to a clinic with expertise in mold exposure. Industrial hygienist and study researcher Michael S. Crandall, CIH, referred nearly all of the patients. Eighty percent of the patients had already hired a lawyer to pursue mold-related claims.

The patients suffered from a variety of possible mold-related health effects, including respiratory symptoms, such as wheezing cough, and nasal discharge, or general complaints, such as skin rashes or joint pain. Yet after rigorous examination — including gathering detailed histories of exposure, home and workplace analysis, blood and skin tests for mold sensitivity, and two years of medical follow-up — there was no link between mold exposure, symptoms, and mold sensitivity.

Leading the study was allergist Jonathan A. Bernstein, MD, an associate professor at the University of Cincinnati, and director of the allergy clinic at the Cincinnati Veteran's Administration Medical Center. He's widely recognized as an expert in the health effects of exposure to indoor pollutants.

"Most people hear 'black mold' and 'toxic mold syndrome' and they are terrified," Bernstein tells WebMD. "A lot of them have symptoms that within a reasonable degree of medical certainty have something to do with their environment. They have a lot of health problems. The mold is black and scary — and to them, it seems the most obvious cause. But the majority of these people were not sensitized to mold."

The Bernstein team's report, in the January issue of Annals of Allergy, Asthma, & Immunology, looked at 135 patients. The researchers have now analyzed more than twice that number of people with possible mold-related health effects. Bernstein says the study findings apply to them, too.

So what caused these people to come down with health effects? All of them had moldy houses or worked in moldy buildings or schools. Many of them were, indeed, allergic to the kinds of mold growing in their environments — although none tested positive for exposure to Stachybotrys — the black mold commonly blamed for "toxic mold syndrome."

The good news is that once the patients got out of their moldy environments — or had them fixed — they got better. Only one patient had long-lasting health effects.

"They do better when they leave these environments, and get worse when they go back in," Bernstein says. "These places have damp conditions. Dampness is clearly shown to correlate with lung problems. Cockroaches, dust mites — not just mold — but a lot of things can grow in damp environments."

Toxic Mold — or Unhealthy Dampness?

Bernstein notes that his team recently evaluated children in a mold-contaminated school. They did find a lot of mold. But they found even higher levels of dust mites and cockroaches. One sick child, Bernstein says, turned out to be suffering not from mold sensitivity, but to cockroach allergy.

"We have to step back and see this as an indoor issue — not just a mold issue," he says. "Mold is an alarm that goes off because we can see it. But there are a lot of invisible factors that can be there as well."

Bernstein says that building problems — homes not properly built, schools poorly maintained — often lie at the heart of these health problems.

"We need to focus on biological agents and toxic gases that accumulate in homes and cause health effects. A lot of people pooh-pooh it, but it happens and people are scared and don't know what is going on," he says. "No one ever measures other air allergens, or other indoor gasses. So there is too little information. But until we better understand home air quality, these mold scares are the kinds of runaway trains that can occur. And this is what this is to some extent — a runaway train."

Toxic Mold Madness

"Mold madness" is what an editorial accompanying the Bernstein study calls it. Pediatrician Michael C. Zacharisen, MD, associate professor at the Medical College of Wisconsin, Milwaukee, co-wrote the editorial with mold expert Jordan N. Fink, MD.

"We are at a pinnacle in the public perceiving a big mold problem. But we are still in the dark ages when it comes to proving if it really is a problem, or what the true mechanism is," Zacharisen tells WebMD. "Science is lagging behind the perception of ill health. Sometimes we try to pin a problem on a particular organism or a particular exposure without having all the science to back it up."

So many lawsuits have been filed over toxic mold, he says, that legal issues have obscured medical science. The Bernstein study, he says, isn't going to change this. But it does open the door for clear-headed scientific research.

"We should not jump to conclusions about toxins until we have had an opportunity to evaluate the more common problems people may actually have," Zacharisen tells WebMD. "People hang their symptoms on what is popular at the time. Some of the more sexy items may bring people to the doctor, but what they actually suffer from may turn out to be something rather routine. Most of the people [with mold exposure] have good old allergies. Straightforward avoidance measures and medications can get their life back on track."

By Daniel J. DeNoon, reviewed by Brunilda Nazario, MD

SOURCES: Bobbitt, R.C. Annals of Allergy, Asthma, & Immunology, January 2005; vol 94: pp 39-44. Zacharisen, M.C. and Fink, J.N. Annals of Allergy, Asthma, & Immunology, January 2005; vol 94: pp 12-13. Jonathan A. Bernstein, MD, associate professor of immunology/allergy, University of Cincinnati; and director, allergy clinic and laboratory, Cincinnati Veterans Administration Hospital. Michael C. Zacharisen, MD, associate professor of pediatric medicine, Medical College of Wisconsin, Milwaukee.