Battling Mold

Molds are simple, microscopic organisms called fungi that are found virtually everywhere, indoors and out. Most live on plant or animal matter. According to the Centers for Disease Control and Prevention (CDC), the number of mold species isn’t known. Estimates range from tens of thousands to perhaps 300,000 or more.

"In terms of allergies, it’s probably not so important to identify a particular mold as to eliminate the conditions that nearly all molds need to grow - moisture, darkness, and poor ventilation," notes David Johnson, Ph.D., professor of occupational and environmental health at the University of Oklahoma Health Sciences Center.

Molds reproduce through spores that can be spread by water, insects, or air, Johnson says. Air currents help mold spores spread. These "baby molds" are so tiny and lightweight they can float through the air like pollen.

When inhaled, molds typically cause nasal and lung symptoms similar to those due to plant pollens, says Warren V. Filley, M.D., an Oklahoma City allergy and asthma specialist and clinical professor of internal medicine at the University of Oklahoma Medical School. Typical symptoms can include nasal and sinus congestion, sore throat, sneezing, watery or burning eyes, dry cough, shortness of breath, and irritation of the nose, throat, or even skin.

What makes mold spores so dangerous for people with asthma remains mostly a mystery for both researchers and clinicians, notes Dr. Filley. Some experts theorize that mold spores’ small size permits them to pass more easily into the lower airway, where they can trigger an asthma attack. Others contend mold spores may also interact with other allergens and environmental air pollution, thus increasing the asthma risk from those substances.

Johnson thinks it’s likely that protein material from molds cause many people to have allergic reactions. "But people also can have an irritant response to some of the volatile chemicals that molds put out," he says.

Amy Duggan, a master home environmentalist with the American Lung Association of Washington, says molds generate the unsightly mildew on bathroom tile. "Never put down carpeting on the bathroom floor because it’s just a reservoir for moisture and helps all kinds of mold to grow," she says.

Indoor molds also lurk in basements, attics, crawl spaces, refrigerators, garbage containers, air conditioners, clothes dryers, upholstery, and house plants. Old books, magazines, and newspapers are also mold breeding grounds that many people overlook, she adds. Other common hiding places include window moldings, shower stalls, or shower curtains. Here, molds may be easy to spot, however, appearing as black, brown, or reddish substances.

Remove visible mold and mildew with a fungicide cleaning product that kills molds on contact. Or, clean with a mixture of one part chlorine bleach to about ten or 20 parts of water. Take care in using such cleaning solutions indoors, since they also can irritate sensitive airways, Duggan cautions.

Johnson says some molds start to grow in environments with humidity levels that are greater than 55 percent, and the majority flourish when it’s above 70 percent. He recommends keeping home humidity or moisture levels at around 50 percent to prevent mold from forming.

Excerpts reprinted from Allergy & Asthma Health magazine, Summer 2000.