Asthma is a common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm.Symptoms include wheezing, coughing, chest tightness, and shortness of breath.
Treatment of acute symptoms is usually with an inhaled short-acting beta-2 agonist (such as salbutamol).Symptoms can be prevented by avoiding triggers, such as allergens and irritants, and by inhaling corticosteroids.Leukotriene antagonists are less effective than corticosteroids and thus less preferred. The prevalence of asthma has increased significantly since the 1970s. As of 2009, 300 million people were affected worldwide.In 2009 asthma caused 250,000 deaths globally. Despite this, with proper control of asthma with step down therapy, prognosis is generally good.
Asthma is clinically classified according to the frequency of symptoms, forced expiratory volume in 1 second (FEV1), and peak expiratory flow rate. Asthma may also be classified as atopic (extrinsic) or non-atopic (intrinsic), based on whether symptoms are precipitated by allergens (atopic) or not (non-atopic). While asthma is classified based on severity, at the moment there is no clear method for classifying different subgroups of asthma beyond this system.Within the classifications described above, although the cases of asthma respond to the same treatment differs, thus it is clear that the cases within a classification have significant differences. Finding ways to identify subgroups that respond well to different types of treatments is a current critical goal of asthma research.
Although asthma is a chronic obstructive condition, it is not considered as a part of chronic obstructive pulmonary disease as this term refers specifically to combinations of disease that are irreversible such as bronchiectasis, chronic bronchitis, and emphysema.Unlike these diseases, the airway obstruction in asthma is usually reversible; however, if left untreated, the...