All about asthma
By Dale Umetsu, MD, PhD
Dale Umetsu, MD, PhD, is a senior associate in Medicine at Children's Hospital Boston. He is board certified in allergy/immunology and pediatrics, with areas of clinical expertise in allergy and primary immunodeficiency. Dr. Umetsu is an internationally recognized leader in asthma and allergy.
What causes asthma?
There are many environmental factors, such as exposure to allergens, viruses and air pollution that may affect the development of asthma. It is also caused by at least a dozen different genes.
The prevalence of asthma has increased dramatically over the past two decades. The number of cases has essentially doubled since 1980, with asthma now affecting about one in 10 children. The increase is thought to be due to changes in the environment, but it's not fully understood yet.
Who is at risk for developing asthma?
The risk factors associated with asthma include a past history of eczema and hay fever (allergies) and a parental history. There is some indication that a reduced number of infections predisposes a child to asthma as well, since having older siblings, early entry into day care and having infections like hepatitis A are all associated with protection against asthma.
How is asthma diagnosed?
It can be diagnosed in several ways. First, a physician may make the diagnosis based on recurrent wheezing precipitated by upper respiratory infections, exercise, exposure to smoke, solvent fumes or air pollution (sulfur dioxide), or exposure to allergens. The diagnosis may also be made based on how these symptoms respond to asthma medications. Other patients may be diagnosed because they have frequent coughing related to infection, exercise or sleep. Finally, the diagnosis can be made based on whether a person's lung function is better or worse after being given small amounts of drugs or medications.
How are asthma and allergies related?
Allergies and asthma often run in the same families, along with atopic dermatitis/eczema and food allergies, since some of the genes that cause asthma also cause these other problems. We know that having hay fever or allergies makes it very likely to later develop asthma—as many as 50 percent of children with hay fever go on to develop asthma—and prevention of hay fever can prevent the development of asthma. In addition, 80 percent of children with asthma have allergies, and exposure to allergens frequently causes an asthma attack. Furthermore, many studies indicate that heavy exposure to allergens, such as cockroaches and dust mites, is associated with the development of asthma. Together these findings indicate that allergies play a major role in the pathogenesis of asthma in most patients.
How can pediatricians work with families to create an effective plan for managing their child's asthma?
Pediatricians can do a great deal. First, they can accurately classify the severity of the asthma by assessing the clinical pattern, using guidelines provided by the National Institutes of Health (NIH). They can also identify the specific risk factors for wheezing in each patient. Based on this assessment, the pediatrician can develop an individualized plan for management that includes how to manage acute attacks, avoid specific agents that cause wheezing and when to seek follow up care. These plans should include the goals of therapy, such as achieving normal activity for the child with minimal to no symptoms, a decrease in emergency room visits or hospitalizations and minimizing side effects from medications. By formulating these plans with the patient and her family, the pediatrician promotes a partnership that encourages greater compliance and ihttp://www.childrenshospital.org/az/Site940/mainpageS940P0.htmlmproved symptom control.
How can pediatricians help children manage their asthma at school?
They should prepare a written asthma management plan that includes plans for handling exacerbations/asthma attacks, access to medications to treat wheezing (self-administration of albuterol, if appropriate), prevention of exercise-induced wheezing and avoiding factors that make the child's asthma worse.
When should a pediatrician refer to a specialist?
There are very specific guidelines from the NIH recommending that a patient should be referred to a specialist: when she is not meeting the goals of therapy; there's severe disease; allergies contribute to the problem, requiring skin testing and/or allergy shots; measurement of lung function is required; complications arise (sinusitis, nasal polyps, vocal cord dysfunction, GE reflux, etc.); or the patient and her family need more advice or education. Regardless of the guidelines, the Allergy and Immunology Clinic at Children's Hospital Boston is always happy to help pediatricians evaluate their asthma patients.
What do you see as the future of asthma treatment?
Our laboratory, like many others, is trying to better understand what causes and prevents asthma. For example, if we understand how viruses like hepatitis A can protect against asthma, we might be able to develop therapies that could mimic the beneficial effects of the infection while avoiding the problems associated with it, thereby preventing asthma and allergies. We and others are also working on developing effective allergen-specific immunotherapies that can alter the underlying disease mechanisms in asthma and allergies, so we can cure these very common problems.
April
2005
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