Molds in the (Indoor) Environment

Molds are a type of fungus that can grow just about anywhere there's moisture. In fact, some molds even live in the human body - usually without causing illness. Only about half of all types of fungi cause disease in humans; these fungal infections - called mycoses - can affect the skin, nails, body hair, internal organs such as the lungs, and elements such as the nervous system.

Although many people can peacefully co-exist with molds, some live in a constant state of siege. Mold spores waft through the indoor and outdoor air continually - this is how they reproduce. When the spores land on a damp spot, they begin growing and digesting whatever they are growing on in order to survive. There are molds that can grow on wood, paper, carpet, and foods. When excessive moisture or water accumulates indoors, mold growth will often occur, particularly if the moisture problem remains undiscovered or untreated.

There is no practical way to eliminate all molds and mold spores indoors. For people with mold sensitivities or allergies, the all-pervading presence of molds in our environment can lead to seasonal or situational symptoms that make them feel miserable.

Reactions to Mold
"Mold can induce allergic disease in susceptible individuals," says Jordan Fink, MD, Medical College of Wisconsin Professor of Pediatrics, Medicine and Allergy & Immunology. "The symptoms of a reaction to house mold are really no different than in the case of an allergy to cats, mites or ragweed."

These include sneezing, runny nose, red eyes and skin rash (dermatitis). And molds can trigger asthma episodes in sensitive individuals with asthma, so people with asthma should avoid contact with or exposure to molds. In addition, Dr. Fink says, "Mold can also induce a condition called hypersensitivity pneumonitis, which has both respiratory and systemic symptoms similar to pneumonia."

Getting Rid of Mold
As with most allergies, primary prevention for a mold allergy or sensitivity is avoidance, says Dr. Fink. "The body usually heals itself of the symptoms, but further avoidance of the mold is the only real therapy."

Even dead mold can still cause a reaction in some people. It's not enough to simply kill the mold, it must also be removed - any areas of mold have to be scrubbed, cleaned scrupulously (with detergent, disinfectant, chlorine bleach or a strong cleaning solution), and dried thoroughly. Do not paint or caulk moldy surfaces.

Mold may be hidden in the back side of drywall, wallpaper or paneling, the top side of ceiling tiles, the underside of carpets and pads, areas inside walls around leaking or condensing pipes, the surface of walls behind furniture (where condensation forms), inside ductwork, or in roof materials above ceiling tiles (due to roof leaks or insufficient insulation).

Absorbent or porous materials such as ceiling tiles and carpet might may have to be thrown away if they become moldy, since mold may be difficult or impossible to remove completely from these surfaces.

The Environmental Protection Agency (EPA) recommends wearing rubber or neoprene gloves, goggles and an N-95 respirator (available in hardware stores) if you are cleaning up mold yourself. If you are unsure about how to clean an item, or if the item is expensive or of sentimental value, consult a specialist in furniture repair, fire or water damage, art restoration, painting, carpet or rug cleaning.

Preventing Mold Growth
Mold spores can't grow without moisture, so the key to mold control is moisture control. If there is mold growth in your home, you'll need to clean up the mold and fix the water problem, or the mold will likely be back. If wet or damp areas and items are dried within 24-48 hours after a leak or spill happens, in most cases mold will not grow.

If possible, keep indoor humidity below 60% (ideally between 30-50%). Relative humidity can be measured with a moisture or humidity meter, a small, inexpensive ($10-$50) instrument available at many hardware stores.

In some cases it may be necessary to install ventilation. Damp places like bathrooms and the areas around clothes dryers might need an open window or a dehumidifier to keep mold from growing. It can also help to run air conditioners during humid weather and use exhaust fans when cooking, dishwashing and cleaning.

Special Cases
House mold can usually be brought under control fairly easily, but Dr. Fink says special caution is called for in some circumstances. "Massive mold exposure, as in uncapping a silo, may lead to pneumonia with millions of mold spores in the lung." This situation can also occur in construction or remodeling, or when removing items with mold under them such as wallpaper, ceiling tiles or paneling.

Most at risk are individuals with compromised immune systems, such as AIDS patients, cancer patients on chemotherapy, and transplant patients. "These patients are more susceptible to fungal invasion, especially with aspergillus," says Dr. Fink. Aspergillus is a common mold, found in soil, decomposing plant matter, household dust, building materials, ornamental plants, items of food, and water. In some, it can cause a respiratory disease called Aspergillosis. "There is no highly successful therapy," says Dr. Fink, "and invasive Aspergillosis is usually fatal in this population."

Some levels of molds usually exist in the home, and most of us can live with them, says Dr. Fink. But if you suspect that mold could be causing health problems, talk to your physician. "Continued symptoms, especially respiratory ones, should be evaluated by an allergist," advises Dr. Fink.

HealthLink Staff

This article includes information from the US Environmental Protection Agency and the Centers for Disease Control and Prevention (CDC).

For more information on this topic, see the HealthLink article Mold Allergies.

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.