Indoor Allergies: the Moldy Truth

Every spring, it's all about hay fever and pollen counts. That's when outdoor allergy sufferers are supposed to stay indoors in the healthier air. But for some people, allergens lurk within their offices or homes.

"With seasonal allergies, people get hit kind of like with a sledgehammer," says James Sublett, an allergist-immunologist and president of the American College of Allergy, Asthma and Immunology. However, he says, "Indoor allergies are more persistent. You get more of a daily exposure that causes chronic inflammation."

Of the roughly 30 percent of Americans who have nasal allergies, about two-thirds have perennial allergies, Sublett says, and for most, the allergy triggers are found indoors. Here's how to avoid the most common allergens that get you right where you live.

Dust, Pets and Pests

Household dust contains a mixture of potential allergy triggers -- notably dust mites. The most common cause of indoor allergies, dust mites love carpeting, pillows, mattresses and upholstered furniture.

Furry animals can also contribute to indoor allergies, even if you don't have pets. "We see a lot of people that are sensitized to animals that don't have animals themselves," Sublett says.

And then there's mice, which can sneak into a house. "A lot of times, people don't even know they've had mouse infestations, and that can be a problem," Sublett says. While mice tend to be more of an issue in inner-city or high-density housing, he says, in his group of Kentucky practices, they see mouse allergies in urban, suburban and rural patients alike.

Cockroach allergies were the major culprits causing health problems in inner-city children with asthma -- hospitalizations, doctor visits, missed school and wheezing episodes -- in a 1997 study in the New England Journal of Medicine. But cockroach allergens are virtually everywhere, concludes a 2012 review in Current Allergy and Asthma Reports.

Mold: Colonizing Your Home

Mold, a type of fungus, thrives on moisture. While it grows outdoors in compost piles, grasses and grains, rotting logs and fallen leaves, mold can find its way indoors, where it colonizes. "It's opportunistic," Sublett says, taking advantage of water damage and flooding. Mold is attracted to humid areas such as damp basements and showers.

Mold often shows up as spots -- usually white, gray, brown, black or green. It can also look like stains on the wall. Musty odors can mean mold. It comes in several varieties, and of those that cause allergic reactions, Aspergillus is the most common. As sensitive people come into contact with mold spores, they can experience sneezing, eye burning, runny nose, coughing, congestion, itching and dry, patchy skin.

When people breathe in mold spores, they may reach the lungs and lead to a serious condition called bronchopulmonary aspergillosis, particularly in vulnerable people who have chronic lung conditions such as COPD or cystic fibrosis.

Insidious Mold

Hidden mold can still affect your health, says Ronald Hoffman, an integrative physician and medical director of the Hoffman Center in New York City, who does the weekly radio show Intelligent Medicine.

"It may be behind a wall; or sometimes what appears to be stains is actually a mold growing on the surface of the ceiling, where there's possibly moisture accumulation or a leak," Hoffman says. You might uncover a growth thick enough to scrape with your finger. Even if mold is deeply buried in Sheetrock, it can make people sick. "After a flood, just forget about it," he says. "You have to really tear out the Sheetrock and replace it."

He recalls the overhyped "deadly mold" headlines in newspapers more than a decade ago, concerning the greenish-black mold called Stachybotrys. In 2001, "it was a late, wet summer with a lot of mold, and people were becoming aware of it," he says. But that kind of mold isn't common, he says, "It's the apotheosis."

With Stachybotrys exposure , he says, "it's a toxic reaction to the nervous system and immune system; and it makes people quite sick beyond sneezing and wheezing." In these rare cases, patients may need to be on steroid medicines and see mold-allergy specialists or clinicians practicing environmental medicine.

Staving Off Allergens

If you or loved ones are vulnerable, you can allergy-proof your home on the following fronts:

Outdoor access. Remove leaves and dead vegetation near the foundations and in rain gutters to promote ground water drainage away from your house, the Asthma and Allergy Foundation of America suggests. You can thin out dense bushes and plants around the foundation as well. Vapor barriers are a first line of defense against condensation on cold walls in winter, along with thick insulation.

Indoor dust. Hoffman recommends a "stripped-down, easily cleanable home, without carpets or rugs" for people who are sensitive. "Indoor plants can be problematic," he adds.

The AAFA has a list of dust-proofing recommendations. No. 1 is encasing mattress and pillows in zippered, dust-proof covers. Next is laundering sheets and blankets weekly in hot water to kill dust mites. Other steps include using roller shades instead of curtains for windows and keeping pets out of bedrooms.

If you're very sensitive, the acts of dusting or vacuuming your home actually can make you sick. Enlist a sympathetic roommate or partner if possible; but if you have to do it yourself, wear a mask.

Humidity. Keeping humidity down helps with both dust mites and mold, Sublett says. It's important to maintain your air conditioning system, have a high-quality, energy-efficient furnace and change filters regularly. Using dehumidifiers also helps.

Bleach products like Clorox can fight mold. Mold-abatement paints and products are available, Hoffman says, and environmental testing services can test home sample panels for mold. If needed, abatement services can remove mold, but costs range widely.

If you're moving into a home, is it worth having it tested for mold? Hoffman says testing "is actually a consideration, if you're sensitive or allergic, or there's a history or likelihood of flooding, or it's a very humid environment."

Coping With Symptoms

Over-the-counter antihistamines can ease milder symptoms of indoor allergies. But "those things won't do" for profound allergies, Hoffman says. "I'm not happy when I hear patients are taking chronic daily antihistamines."

Sublett says for most people with moderate to severe allergies, OTC drugs "are not going to be that effective. Even the prescription medicines have limitations."

For people who've tried obvious measures and still have a problem, Sublett says it's time to see an allergist for evaluation "and really find out what you're allergic to." You may be surprised at the answer, he says. It could even be something such as an irritant reaction to scented candles or plug-in air fresheners, or an avoidable allergen.

"Of course, allergy immunotherapy is also quite effective for dust mites, animals and that sort of thing," Sublett says. "That's an option people have." The important thing, he continues, is not to just accept symptoms that make people miss work and school and feel miserable. "By identifying the allergens and really treating them," he says, "it can be a game-changer as far as improving their quality of life."

Lisa Esposito is a Patient Advice reporter at U.S. News. You can follow her on Twitter, connect with her on LinkedIn or email her at lesposito@usnews.com.