When Alexandria resident Trish Thackston learned that her 11/2 -year-old son Connor had asthma, she and her husband, Chris, did everything they could to reduce the boy's exposure to triggers that set off his asthma attacks, which at times sent him to the emergency room.

A skin allergy test had shown that Connor was severely allergic to dust mites, tiny insects that feed on human and animal skin flakes and commonly infest mattresses, bedding, stuffed animals, upholstered furniture, carpets and curtains. He also had mild sensitivity to other environmental allergens.

An allergist gave the Thackstons a stack of brochures and booklets about steps to take and products to buy. He also reviewed protocols for controlling dust mites in the home. Afterward, the couple realized that their apartment's old carpeting and poor ventilation may have been aggravating Connor's asthma. "So we ended up actually moving," Trish Thackston said. "We ended up buying a house with hardwood floors."

The efforts didn't end there. The couple had their new home's ventilation system thoroughly cleaned before moving in, and they ditched their upholstered furniture in favor of leather. They covered Connor's mattress, box spring and pillows in mite-proof encasings. They also dusted and mopped every two or three days, Trish Thackston said, and washed Connor's sheets weekly in hot water. The Thackstons' commitment to allergy-proofing their home seems to have worked: Connor, now 6, has been off asthma and allergy medication since age 4.

But a new study, published in this month's Journal of Allergy and Clinical Immunology, suggests that many parents of children with asthma don't do as well. The study shows that parents implement some widely recommended measures to rid their homes of things likely to trigger an asthma attack. But they also take other, sometimes more expensive actions that were not likely to be useful. And they often fail to take other measures that could be more beneficial.

In 2002, 20 million people in the United States were reported to have asthma -- a chronic inflammatory lung disease characterized by wheezing, difficulty breathing, chest tightness and coughing -- according to the National Heart, Lung, and Blood Institute (NHLBI). About 6.1 million were children under age 18. Asthma attacks occur after exposure to environmental allergens (such as animal dander, mold and pollen), irritants (such as cigarette smoke, strong odors or air pollution), viral infections and some medications.

The new study found that parents often invest in expensive HEPA filters for vacuum cleaners and ventilation systems -- both steps recommended by NHLBI. But some still allow cigarette smokers to light up around the child (or continue to smoke themselves), or keep windows open, allowing pollen into the home.

Four out of five parents surveyed reported knowing of "at least one environmental trigger of their child's asthma," according to the study. Of those families, about 81 percent attempted "some action to remediate or remove it. However, most of these actions were not specifically endorsed by current NHLBI asthma guidelines."

Of 1,788 actions parents described taking, more than "half were not included in NHLBI recommendations and were not likely to be useful in controlling the trigger that the parent reported," the authors wrote.

Nineteen percent of respondents made no attempt to address environmental triggers of their child's asthma.

Smoke Blind

The five most common actions parents reported taking were purchasing special air filters (25 percent of all survey respondents); reducing their child's exposure to dust (22 percent); using a special vacuum cleaner (17 percent); purchasing mattress, comforter and/or pillow covers (16 percent); cleaning the home more often (13 percent); and reducing the child's exposure to animals (11 percent).

Despite NHLBI's caution that tobacco smoke is "the most important environmental indoor irritant," just 7 percent of study participants in smoking households reported "any attempts to reduce or eliminate smoke exposure," according to the study. Smokers were present in 24 percent of the households surveyed.

"Parents [will] . . . pursue a lot of elaborate actions as opposed to the most straightforward one," study co-author Michael D. Cabana, a professor of pediatrics at the University of Michigan, said in an interview. That "tells me that sometimes the most straightforward action -- quitting smoking -- might not be the simplest and easiest for parents."

Martha White, a physician at the Institute for Asthma and Allergy, a private practice in Wheaton and Chevy Chase, said parents of children with asthma should make that sacrifice. "Parents should stop smoking, and if they can't, they should limit their smoking to outdoors," she said.

The survey is part of a larger University of Michigan project called the Physician Asthma Care Education program (PACE), an effort sponsored by the New Jersey-based Robert Wood Johnson Foundation. PACE aims to improve the way doctors counsel and educate parents and kids with asthma. In this portion of the five-year project, researchers conducted telephone interviews with 896 parents of children with asthma ages 2 to 12. Survey respondents were randomly selected from the clientele of 106 primary care physicians participating in a trial for PACE, according to Cabana.

"The whole purpose of the [PACE] study is to understand what physicians can do better," Cabana said. "As physicians we need to do a better job putting the information that [parents] get in context with their child's asthma. Every child with asthma is different, and it's important to tailor a child's asthma regimen to what works best for that particular child."

Under Their Noses

White said the most common allergens in children under 4 are animal dander, mold and dust mites.

"I have them [parents] do the allergy encasings [and] try to keep the stuffed animals out of the bed," White said. She also advises parents to check for mold in their homes -- particularly in basements -- and keep kids out of the bottom of bunk beds because the mattresses above and below can be ripe with dust mites.

For kids who are allergic to pets, White said, "at a minimum, we want the animal out of the house." She recommends keeping the animal outdoors or getting rid of it altogether. Starting the child on allergy shots, or immunotherapy, to desensitize them to the animal is another option.

The NHLBI guidelines indicate that doctors play an important role, too.

"Clinicians should identify triggers, refer patients as needed for allergen testing and educate patients about triggers and possible control measures," the study said.

The study's authors said the results confirm findings that physicians are not good judges of which parents will follow their advice.

"Physicians have been shown to be inaccurate when predicting which parents will adhere to their therapeutic recommendations," the study said. "We found no demographic characteristics [such as race, age, or economic status] to be associated consistently with taking environmental actions."

Trish Thackston said when Connor was tested for allergies at age 5, he was no longer sensitive to dust mites or the other environmental allergens he had reacted to four years earlier. But his parents still maintain an asthma-friendly environment.

"It just seemed to be prudent not to give it up," Thackston said. "We're not as fanatic about the cleaning as we were when he was having problems, but we do keep all of the [mite-proof] covers on."

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Trish and Chris Thackston of Alexandria, pictured with daughter Mia Rose, 2, and Connor, 6, successfully allergy-proofed their new home to avoid triggering Connor's asthma.A microscopic dust mite is one of many environmental asthma triggers hiding in home carpets, upholstery and bedding.