What is asthma?
Asthma is a complex clinical syndrome of chronic airway inflammation characterized by recurrent, reversible, airway obstruction. Airway inflammation also leads to airway hyperreactivity, which causes airways to narrow in response to various stimuli.
Asthma is a common chronic condition, affecting approximately 8% to 10% of Americans, or an estimated 23 million Americans as of 2008. Asthma remains a leading cause of missed work days. It is responsible for 1.5 million emergency department visits annually and up to 500,000 hospitalizations. Over 3,300 Americans die annually from asthma. Furthermore, as is the case with other allergic conditions, such as eczema (atopic dermatitis), hay fever (allergic rhinitis), and food allergies, the prevalence of asthma appears to be on the rise.