Indoor allergens & women's health.

Laura Martin is only 19, but already the college sophomore knows more than she ever wanted to about indoor allergens. She knows that her allergies to mold and dust mites meant ripping up the carpet in her childhood bedroom, getting rid of the spa and wooden deck just outside her bedroom and replacing the sliding glass doors in that room, because mold grew on them.

Now that she lives in a sorority house at the University of Idaho in Moscow, ID, however, things are a bit more complicated. After all, she can't make major changes to a home she doesn't own. So, she's doing what she can to avoid mold spores and dust mites: She covers her mattress and pillowcases in her sorority house with allergen-proof zippered covers and tries to find low-allergen environments in which to study.

Ms. Martin is just one of the 40 to 50 million people in the United States living with allergies--one of the most common chronic diseases in this country, according to the Asthma and Allergy Foundation of America.

Some are allergic to certain foods, medications or insect bites. But the vast majority are allergic to something in their environment--pollen, dust mites, mold, animal dander or cockroach droppings.

While such an allergy may mean nothing more than a runny nose and itchy eyes, for some it can lead to asthma, a potentially life-threatening condition that kills about 4,200 people a year, according to the U.S. Centers for Disease Control and Prevention (CDC). (1) A national survey conducted by the American College of Allergy, Asthma & Immunology (ACAAI) in August 2002 found 94 percent of allergy sufferers reported that allergies affected their quality of life, including work productivity, sleep, concentration and even sex. (2)

But perhaps the most disturbing statistic has to do with the growing prevalence of allergies and asthma. A study published in the July 2005 issue of the Journal of Allergy and Clinical Immunology found that more than half of Americans aged six to 59 had a reaction to at least one of 10 common allergens between 1988 and 1994, 2.1 to 5.5 times higher (depending on the allergen) than when similar tests were conducted between 1976 and 1980. (3)

Meanwhile, the CDC reports that the prevalence of asthma in the U.S. increased nearly 74 percent between 1980 and 1996. (4) By 2002, an estimated 20 million people had asthma (72 out of every 1,000 people). (1) And, as with many chronic diseases, the burden falls heaviest on minorities, particularly African-American children, who tend to have the highest rates of asthma. (5)

So what's going on?

Before we talk about the theories behind the increase in asthma and allergies, it helps to understand just what asthma and allergies are.

An Immune System Run Amok

Allergies are an overreaction of your immune system to an otherwise harmless material. It could be a dietary ingredient, as in food allergies, a grain of pollen, as in seasonal allergic rhinitis (aka, hay fever), or a mold spore, as in perennial, or year-round, allergies.

This overreaction generally occurs after multiple exposures to the potential allergen, explains Anne-Marie A. Irani, MD, who chairs the Division of Pediatric Allergy, Immunology and Rheumatology at Virginia Commonwealth University in Richmond. "You don't inherit an allergy. You inherit the tendency to become allergic to a particular thing if you're exposed to it enough," she says.

If you are genetically predisposed to allergies, following exposure to an allergen, your body's immune system's cells produce antibodies called IgE, or immunoglobulin E. They stick to inflammatory immune system cells like mast cells or basophils and just hang out there, not hurting anyone. But one day a grain of grass pollen makes its way into your nose, or a peanut protein passes through your intestine and gotcha!

The camel's back has finally broken, and your immune system launches an all-out, no holds-barred attack on that "invader." The antibodies signal mast cells and basophils to release inflammatory chemicals such as histamine, prostaglandins and leukotrienes, which, in turn, trigger allergy-related symptoms like runny nose, scratchy eyes and sneezing.

Asthma takes this allergic reaction one step further. With asthma, an allergic reaction also triggers a reaction in the immune system cells lining your airways. (6) They react by producing sticky mucus that clogs air tubes. At the same time, other airway cells become inflamed causing the tubes to swell and spasm, making it hard to breathe. Over time, the very nature of your respiratory passages change--and not for the better.

Not all asthma is triggered by allergens, however. Exercise, irritants in the environment, such as chemical fumes, perfume, cold air and smoke, even aspirin and other non-steroidal anti-inflammatories, can trigger asthma.

Although there are no differences in rates of allergies between men and women, asthma is more prevalent overall in women after puberty, about 30 percent higher. (1)

It also tends to be more severe in women, notes Marianne Frieri, MD, PhD, professor of medicine and pathology at State University of New York at Stony Brook and director of allergy/immunology at Nassau University Medical Center in East Meadow, NY. Plus, women are more likely than men to be seen in the emergency room and admitted to the hospital for their asthma. (7) The reasons vary, says Dr. Frieri.

One has to do with the effect of reproductive hormones on asthma. For instance, up to 40 percent of women with asthma report their symptoms get worse just before and during menstruation. (8) Studies also find that mast cells become more active just before and during menstruation, (9) and that women with asthma and allergies have a greater response to allergen skin tests when they're menstruating. (10) There's even some evidence that oral contraceptives can make asthma worse in women. (11)

Understanding the Increase

So what's behind the overall increase in asthma and allergies? There are many theories. One theory has it that people spend considerably more time indoors these days than they used to, says Samuel J. Arbes Jr., PhD, an epidemiologist at the National Institute of Environmental Health Sciences. That, in turn, increases their exposure to indoor air pollution and allergens.

Plus, today's homes are constructed differently than homes of past years, with tighter windows that are rarely opened and doors that allow in less fresh air, trapping more allergens, notes Jeffrey May, the author of The Mold Survival Guide and My House Is Killing Me!, and president of May Indoor Air Investigations, LLC, in Cambridge, MA.

That might not sound too bad until you consider that government studies find the air inside our homes and buildings is more polluted than the air outside. And, considering that most of us spend about 90 percent of our time indoors, that means our exposure to those pollutants is far greater than our exposure to outdoor pollutants. (12)

Next comes something called the "hygiene hypothesis," which holds that because we're exposed to fewer germs while we're young--through our emphasis on cleanliness, overuse of antibiotics, and immunizations--our immune systems never learn the difference between benign invaders like mold spores and dangerous invaders like bacteria. So it overreacts to everything.

"The bottom line is that we don't know for sure why there is a rise in the prevalence of asthma and allergic disease," says Dr. Arbes. "That's what a lot of researchers are trying to figure out."

Identify the Allergens

What can you do to reduce your body's reaction to indoor allergens and asthma-triggers? The first step is to find out what you're allergic to. The best way to do this is to see an allergist for a series of skin prick tests that expose you to a tiny bit of the allergen to see if you develop a welt at the site of the skin test. Once you know your allergy or asthma triggers, you can try to take steps to avoid them.(6)

Here's a quick look at the most common indoor allergens:

* Dust mites. Dust is one of those things you simply can't escape. To call it "dust," though, hides its true nature. Dust is mostly human skin flakes, but also includes pollen, pet dander, and dust mites and their droppings. These miniscule, eight-legged insects live in anything soft--furniture, cushions, carpeting, bedding--and dine every day on those flakes of your skin.

That's why if you are allergic to dust mites, you probably wake up congested in the morning. Blame the tiny creatures who call your pillow, mattress and quilt home. In fact, the bedroom is a primary danger zone in your home for allergies.

* Animal dander. Even if allergies forced you to give up a pet, that doesn't mean the pet dander is gone. When Dr. Arbes and his colleagues surveyed homes around the country, they found every one contained dog and cat allergens. A large percentage of homes had levels high enough to increase the risk of allergies--whether or not the home contained a pet. (13) In another study, they even found high levels of dog and cat allergens in pet-free day-care centers. (14)

That's because microscopic dander particles travel and stick on clothing and other objects. Because it's so sticky, he says, it's probably impossible to eradicate dander from your environment.

* Mold. When we talk about mold as an allergen, we're not talking about the kind of "killer" mold dramatized in the media. But common household molds, or more specifically mold spores, are definitely allergens, triggering respiratory symptoms in susceptible people and making asthma worse. (15)

You'll never get rid of it all. Mold spores are everywhere, with possibly hundreds of thousands of different species. (15) You can even find airborne spores in Antarctica. (16)

Mold thrives on dampness and dies in dryness, which is why our room-by-room recommendations on page 4 focus on reducing dampness. A big contributor to mold growth is air conditioning, says Mr. May.

When he compared 600 "sick" houses to 300 control homes, he found the likelihood of having respiratory problems was twice as high if the house had central air conditioning than if it didn't.

Blame the way air conditioning works: When you cool warm, moist air, you produce water. That means air conditioning coils are always wet, providing a great spot for microbial growth. Once the liquid dries (in the winter, for instance), the microbes and their allergens remain, becoming airborne.

* Cockroach droppings. "Cockroach allergy is on the rise, particularly in the inner city," says Shelly M. Harvey, MD, a Dallas-based allergist. Yet Dr. Irani also sees it in kids from suburban environments as well. "We used to only test kids for cockroach allergies if the parents admitted there were cockroaches in the house," she says. "We now test routinely and find some of our most affluent patients sensitized to cockroach droppings."

That doesn't mean you have the bugs in your house. "Schools, theaters and restaurants have cockroaches," she says. As do luxury high-rise apartments, where they skitter between dwellings via water pipes and inside walls.

Room-by-Room

Some of the simplest and least expensive strategies can make a big difference in your asthma and allergy symptoms. (17) Here's a room-by-room list of how to decrease indoor allergens. (18)

Whole house

* Wherever possible, tear up carpeting and replace with a hard-surface flooring.

* Install a whole-house pleated media filter in your heating/air conditioning system with a Minimum Efficiency Reporting Value (MERV) rating of at least 8.

* Don't overwater houseplants. It could cause mold growth if water leaks onto flooring.

* Vacuum with a machine equipped with a HEPA filter and empty contents outside.

* HEPA-vacuum walls, baseboards and radiators once a year to clean off dust.

* Clean areas of the home prone to mold growth with a bleach-based cleanser, which kills and denatures the mold spores, eliminating their allergenic properties.

* Replace heavy draperies with easy-to-clean metal blinds or wood shutters.

Entrance

* Use a washable mat by the door to catch allergens you might otherwise track inside.

* Leave shoes at the front entrance to prevent tracking dust, molds and pollen into the house.

Bathroom

* Keep the door and/or window open when showering so steam can escape.

* Install a new exhaust fan to vent warm, damp air and run it any time you take a shower.

* Wipe down walls, floors and all surfaces with a mold-killing cleanser every week.

* Wash bathroom curtains in bleach and hot water regularly.

* Wash and dry bathmats weekly to kill dust mites and prevent mold.

* Clean tile and grout, window sills and countertops with a mold-killing product or bleach-based solution.

Bedroom

* Encase quilts, pillows, mattress and box spring in allergen covers.

* Wash all linens in very hot water weekly to kill dust mites.

* Use a portable HEPA-air purifier in the bedroom and keep pets out.

Kitchen

* Clean the tray under the refrigerator with a bleach-and-water solution often to prevent mold growth.

* Check for leaks or dampness under the sink and make repairs to reduce moisture.

* Wipe sides of oven, refrigerator and backsplashes with mold-preventing cleanser every week.

Laundry Room

* Vent your dryer to the outside so that the moisture and lint it pulls out of your clothes doesn't go into the house to become a mold magnet.

* Don't leave damp, wet clothes sitting around waiting to be washed.

Basement

* Inspect space for moisture and mold. If you find any, clean with a bleach solution.

* Have central air conditioner trays and coils cleaned annually.

* Clear out old stored papers and fabrics that can become moldy.

* Check visible insulation for dampness, and replace if even slightly wet.

* Use a dehumidifier with a MERV 8 rating.

* Keep the humidity in your finished basement below 50 percent.

Resources

Asthma and Allergy Foundation of America (AAFA)

202-466-7643

www.aafa.org

Offers information about asthma and allergies, and educational programs for consumers and health professionals.

American College of Allergy, Asthma & Immunology (ACAAI)

847-427-1200

www.acaai.org

Offers extensive consumer/patient information on allergies and asthma.

American Academy of Asthma, Allergy and Immunology (AAAAI)

414-272-6071

www.aaaai.org

Presents a range of print and online asthma and allergy information.

U.S. Centers for Disease Control and Prevention (CDC)

CDC Health Topics: Asthma & Allergies

www.cdc.gov

Offers range of information about allergies and asthma and national programs that provide resources.

RELATED ARTICLE: Using Household Cleaners Safely

Grabbing a bottle of bleach or bleach-based household cleanser to tackle that moldy bathroom wall? Then follow these recommendations from the CDC to ensure safe use (11):

* Never mix bleach with ammonia. The two together can produce dangerous, toxic fumes. And just because your product isn't pure bleach, it might still contain bleach. Read labels.

* Open windows and doors to provide fresh air.

* Wear non-porous gloves and protective eyewear.

* Always follow the manufacturer's instructions.

* Cleaning may trigger symptoms for people with allergies and asthma. Consider asking someone else to apply all cleaning products.