As mentioned in causes asthma, the development of asthma is thought to arise from complex and poorly understood interactions involving a person’s inborn genetic characteristics and elements of the environment in which he or she lives, from birth onward. Each of us is endowed with a specific set of genes, inherited from our parents, and there is obviously nothing we can do to alter our genetic makeup.
We might thus logically turn our focus to what constitutes the elements of the environment in which we live to see if any preventive measures could prove helpful. An emerging body of scientific evidence suggests that infection with certain common strains of respiratory viruses early in life may predispose a child to develop asthma. Although interesting and a guide for additional research into such viruses and their relationship to asthma, the observation does not carry practical “real life” implications. How, indeed, to avoid a common respiratory virus? There is no feasible way for any of us to avoid catching one! Over what other parts of our environments might we have more “control”? We can, of course, modify specific exposures in our indoor environments and in particular, in our homes.
In 2000, the Institute of Medicine published a report called Clearing the Air: Asthma and Indoor Air. It reviewed the available scientific evidence about indoor air exposures and asthma. One aspect of the report looked at those exposures that might represent risk factors for the development of asthma. It concluded that there is sufficient scientific evidence to support a causal relationship between the development of asthma and exposures to house dust mites as well as a strong association between exposure to secondhand smoke (called ETS for environmental tobacco smoke) and asthma in younger children.
The ETS exposure included prenatal exposure. Exposure to cockroaches and to the respiratory syncytial virus (RSV) were less clear cut risks for asthma, but both appeared to increase the risk. Not everyone at an increased risk for asthma will inevitably go on to develop the condition, but it is both prudent and reasonable to decrease or eliminate exposures to known risk factors as much as is possible. In advising a patient, I would focus on lessening exposure to house dust mites, secondhand smoke (ETS), and cockroaches. I would especially emphasize that it is imperative that any woman who smokes be aggressively counseled and assisted in quitting during pregnancy and beyond. The vigorous anti tobacco approach should continue after the baby’s birth and extend to any other household members who smoke to ensure that the home becomes and remains 100% smoke free. Similarly, pediatricians and allergists often make suggestions in an attempt to modify the emergence of allergies and/or asthma in a child thought to be at increased risk for the development of the disease, based on a family history of either allergy or asthma in a parent or older sibling.
They may for instance, advise new parents with asthma to follow special guidelines in caring for their newborn. Recommendations typically concern the baby’s diet and environment. For example, an exclusive diet of mother’s milk for at least the first 4–6 months after birth appears to delay (but not necessarily avert) the development of allergy and asthma. Similarly, early introduction of solid food is frowned upon in an infant at increased risk for asthma. Certain highly allergenic foods should not be part of a toddler’s diet, because of the association of allergy and asthma in youngsters. The foods responsible for most food allergies in children include cow’s milk, eggs, nuts, and fish. More specifically, 90% of all allergic reactions to food are caused by eight foods: cow’s milk, egg, peanut (peanuts are legumes, not true nuts), tree nuts (such as walnuts, cashews, and hazelnuts), fish, shellfish, soy, and wheat. In addition to dietary guidelines, physicians stress the importance of a smoking ban at home.
Some pediatric specialists may advise a bedroom free of dustcollecting items such as draperies, stuffed animals, and wall to wall carpeting, and they may recommend encasing bedding in specialized covers (encasements) to reduce dust mite exposure. Dr. Homer A. Boushey is a world renowned authority on asthma and a professor of medicine at the University of California, San Francisco. In a recent article in the Proceedings of the American Thoracic Society medical journal, Dr. Boushey recapped recent asthma developments as presented at the 2008 Thomas L. Petty Aspen Lung Conference devoted to asthma insights and expectations. He bluntly addresses the frustrating lack of an effective and accessible means of asthma prevention and elaborates: It is clear that the lay public ultimately expects the development of a cure for those with asthma and of an effective means of primary prevention for those who do not yet have it. They understand that fulfilling these expectations will require good understanding of the causes and mechanisms of asthma, so they appreciate the need to do research, but they don’t want us to take too long about it . . . As for prevention, medical science is seen as almost clueless.
We know to advise people to avoid exposure of children to secondhand cigarette smoke, to breastfeed babies for 6 months but maybe not longer . . . But we don’t seem to know whether to advise buying two dogs or two cats, to avoid peanuts or eat them early, to send young children to daycare to ensure they contract multiple viral respiratory infections or to treat them with immune globulin for RSV bronchiolitis. The bottom line is that although experts recommend reducing environmental exposures that have shown to be asthma risks, there is no known intervention at the present that completely prevents the development of asthma. It is important to note that a child may develop allergy or asthma (or both) even though his or her parents have meticulously followed all of their physician’s advice.
Neither the child nor the parents are in any way “responsible” for the development of the asthma. If you or your youngster has been diagnosed with asthma, there is no point in resorting to a should have, could have, would have mindset, especially given the fact that there is no proven intervention or behavior that confidently completely prevents allergies or asthma. Instead, commit yourself to successfully managing your asthma and its symptoms. Once an individual of any age is diagnosed with asthma, initial treatment concentrates on gaining control of the asthmatic episode and on restoring normal lung function. After the initial treatment goals are met, the major focus of contemporary treatment then emphasizes prevention of symptoms such as breathlessness, chest discomfort, cough, mucus production, and wheezing.
One class of asthma medications, referred to as “controller” or “maintenance” medicines, is specifically designed and prescribed to maintain normal lung function and to prevent an exacerbation of asthma—what used to be called an asthma attack (see Questions 12 and 14 for more on this subject). Identification of an individual’s asthma triggers and avoidance of exposure to those triggers are, in addition to using controller or maintenance medications, other means of successfully preventing asthma exacerbations. You can read more about asthma triggers in Question 41.
Kerrin’s comment:
From infancy, my son experienced allergic symptoms. He developed eczema when he was a few months old and would occasionally get hives after he breastfed. He later experienced breathing problems that on three separate occasions escalated to the point where he needed to be hospitalized for around the clock breathing treatments. When he was about 2 years old, he was officially diagnosed with asthma. Knowing this, and that he had allergic tendencies but not knowing exactly what they were yet, we decided to keep him away from the highly allergenic foods, such as peanuts and cow’s milk.
As he got older, we would give him small portions of milk to see if he could tolerate it and he seemed to be fine. Because peanuts are the next hardest ingredient to avoid, we decided that we would have him tested for this allergy. Before we even got the chance, he took a bite of a cookie that had either been baked with peanut oil or had touched another item that contained peanut, and he shortly thereafter developed terrible hives. We immediately took him to see a pediatric allergy specialist, who tested him for peanuts, and, sure enough, he had a severe allergy. We were told that the next time he is exposed to peanut, the symptoms could be even more severe and lead to compromised breathing.