Mold Allergy Self-Defense

Mold allergies are more common in warm weather, but can be a year-round problem. Here’s what to do.

Medically Reviewed by Brunilda Nazario, MD on July 23, 2009
4 min read

Alternaria. Aspergillus. Cladosporium. Penicillium. Unless you have a special fondness for fungi, you’re probably not too familiar with these or any of the thousands of other common molds.

But if you’re among the estimated 5% of Americans who have mold allergies, you may be all too well acquainted with the itchy eyes, nasal congestion, coughing, wheezing, skin irritation, and other symptoms mold allergies can cause. Severe mold allergies can even trigger potentially dangerous asthma attacks.

Mold allergies are more common in warm weather, but are essentially a year-round problem in some parts of the country.

Like other common allergies, mold allergies arise when the immune system mounts a vigorous reaction to an ordinarily harmless substance or organism -- in this case the microscopic spores that float in the air indoors and out. And as with other allergies, mild symptoms of mold allergies can often be controlled with over-the-counter antihistamines and decongestants and prescription steroid nasal sprays. In severe cases, allergy shots are generally effective.

But experts agree that mold allergy sufferers are better off avoiding mold in the first place.

That means steering clear of places where mold is likely to lurk: decomposing vegetation (think compost piles, decaying leaves, wooded areas, etc.) as well as antiques shops, flower shops, farms, summer cottages, greenhouses, saunas, and anyplace else where warm, damp conditions prevail.

Most important, it means taking steps to ensure that your home -- where the average American spends 90% of the time -- is a mold-free zone.

Does that mean you’ll have to give up the Stilton? Probably not. “Cheeses and other moldy foods can bother some people with mold allergies, but generally this isn’t a problem,” says James L. Sublett, MD, chief of pediatric allergy and immunology at the University of Louisville School of Medicine in Louisville, Ky., and vice-chairman of the indoor environments committee of the American College of Allergy, Asthma, and Immunology.

Here are some other six strategies that can make a big difference in containing mold.

Periodically check your roof and the household plumbing. Look under sinks, inside showers, around windows and doors, and inside closets. If you have a basement, check the floor and walls for signs of water infiltration. If you find a leak, repair it right away. Sometimes pipes spring a leak within the walls or floors, so you may have to do a bit of searching to find them.

Just because you don’t see mold “doesn’t necessarily mean you are in the clear,” says Nathanael S. Horne, MD, clinical assistant professor of medicine at New York Medical College in Valhalla and an allergy specialist in private practice in New York City. “Even if you don’t see any mold, if you are experiencing unexplained symptoms and have eliminated other culprits, it could be mold.”

Most indoor mold can be eliminated simply by getting rid of the mold item or by wiping the affected surface with diluted bleach (one cup of bleach per gallon of water). Be sure to wear goggles and rubber gloves. If that doesn’t work, you may want to call in a professional company that rids houses of mold.

If you or someone you live with is allergic to mold, your goal should be to lower humidity in your home, not raise it. So forget about using a humidifier or vaporizer.

“Adding moisture is the last thing you want to do,” says Sublett. “There’s no evidence that humidifiers have health benefits, and lots of evidence that they promote the growth of mold.”

Pick up an inexpensive moisture meter (hygrometer), and take readings throughout your home. Pay special attention to bathrooms, the basement, and kitchen.

If the humidity exceeds 50% in any room, find ways to bring it down. One possibility is to boost ventilation by installing (and using) exhaust fans. If this doesn’t do the job, get a dehumidifier.

“Look for one that attaches to a central drain or to your heating and air conditioning system,” says Sublett. “Otherwise, you may find yourself spending all your time emptying buckets of water.”

Mold spores get stirred up every time you sweep, vacuum, or do yard work. To protect yourself at these times, use a vacuum cleaner with a built-in HEPA air filter, and wear a filtration mask that is rated “N95” by the National Institute of Safety and Health (NIOSH).

If possible, the mask should stay on for a couple of hours after you stop. It can take that long for spores to settle out of the air.

As long as there is sufficient warmth and water, mold can grow on all sorts of common household items, including wood, paper products, foam rubber, wallboard, and carpet. Indoor plants can harbor mold as well.

If mold is a problem in your home, de-cluttering can help. Also, get rid of wall-to-wall carpeting in dank basements, steamy bathrooms, and in your bedroom, where you spend so much time.

Equip your furnace with a high-efficiency filter that has a Minimum Efficiency Reporting Value (MERV) rating of at least 11. Replace the filter every three months, and have your furnace serviced every six months. It’s also a good idea to put a HEPA air filter in your bedroom and in any other rooms where you spend significant amounts of time.