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What is Asthma?

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Asthma is a chronic lung disorder of huge public health significance.  Asthma occurs when the body's immune system recognizes common and harmless substances found in the environment, such as dust mites ( see this page about dustmites ), as "foreign".  When these substances are inhaled, the immune reaction can cause inflammation in the airways, which narrows them and makes breathing difficult.  Symptoms of include intermittent bouts of wheezing, shortness of breath, and cough. Asthma is recognized reversible airflow obstruction, airway inflammation, and increased airway responsiveness to a variety of nonspecific stimuli. Asthma is one of the most significant chronic diseases in children afflicting 8-12% of the population with a disproportionately high prevalence among minorities and poorer groups. 

Asthma is particularly widespread in inner-city communities. Asthma is the most frequent cause of pediatric emergency room use and hospital admission and is the leading cause of school absences. The economic costs of asthma are staggering and estimated at more than $10 billion/year in the U.S. alone. Despite improvements in asthma diagnosis and management, and medical science, the incidence of and death rate from asthma has greatly increased over the past 15 years. Importantly, asthma prevalence and mortality rates are nearly three-fold higher among African-Americans than among Caucasians.

There seems to be a link between asthma and allergies.  More than 70% of patients with asthma have positive skin test reactions to common household allergens. An allergist can give you a skin test for allergies; this may also show that you could have asthma. Childhood is the most common time for sensitization to these allergens to occur. Studies in children with asthma suggest that allergy influences the development, persistence, and severity of the disease. Children spend the majority of their time at home and the indoor home environment contains many allergens. For example, house dust contains a mixture of allergens from domestic animals (cats, dogs, birds), insects and microscopic arthropods, bacteria, and fungi. Several recent studies have demonstrated that sensitization to the house-dust mite allergens Der p I and Der f I are strongly associated with asthma. In low income areas, sensitivity to the cockroach allergens Bla g I and Bla g II are also important. In addition, cat allergy may be a significant risk factor for attacks of asthma and the most important cat allergens are Fel d I and cat albumin.

Family genetics are important in allergy and asthma. For example, the about 30% of the general population have positive results in the allergy skin tests, but children of parents with allergies have remarkably higher (60-70%) positive rates in skin tests. Similarly, the occurrence of asthma increases more than three-times (up to 20-27%) in individuals with a positive family history for asthma. The prevalence may be even higher if both parents have a history of asthma. A family's predisposition to asthma may involve genetic factors as well as environmental, economic, and social factors. Exposure to tobacco smoke (including second-hand, passive smoking) also is associated with an increased risk of wheezing in infants and recurrent wheezing in non-allergic children and in atopic females.

Upcoming web pages here will have more articles about asthma. They will contain important information on what we as parents can do to minimize exposure of our children to potentially harmful indoor allergens. 

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