Asthma is a chronic condition in which a person s airways occasionally become inflamed, which causes swelling that obstructs airflow to the lungs. It is one of the most common chronic illnesses in the United States, and while prevalence varies by gender, race, and geographic region, it currently affects over 20 million people in this country alone. There was a dramatic spike in diagnoses of asthma between 1980 and the late 1990 s, but the number of total cases has since been stable. Mortality has been slower to decline, however, and about 11 people still die from asthma in the US each day.
Despite advances in our understanding of the factors contributing to asthma, the cause of asthma remains unknown. There is a strong association between allergies and asthma, and some people appear to be genetically predisposed to the illness. Several hypotheses have been proposed to explain the increase in asthma prevalence in recent years. Many of these ideas focus on characteristics of lifestyles that have accompanied increasing levels of industrialization around the world. Additionally, exposure to tobacco smoke, both in utero and during early life, increases the risk of developing asthma. There is less evidence to support the idea that early exposure to viral infections, pets, air pollution, and certain diets may also cause asthma.
Asthma therapies are divided into two general groups: reliever therapy is used for immediate relief of symptoms such as wheezing and coughing, and daily controller therapy is used to treat airway inflammation and prevent symptoms from developing. Asthma control should be reassessed regularly, and therapy should be modified accordingly. The development of new asthma treatments may improve our understanding of the disease.