Asthma (from ásthma "panting) is the 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. Asthma is clinically classified according to the frequency of symptoms, forced expiratory volume in 1 second, and peak expiratory flow rate. Asthma may also be classified as atopic or non-atopic. It is thought to be caused by a combination of genetic and environmental factors. Treatment of acute symptoms is usually with an inhaled short-acting beta-2 agonist. 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. Its diagnosis is usually made based on the pattern of symptoms and/or response to therapy over time. The prevalence of asthma has increased significantly since the 1970s. As of 2010, 300 million people were affected worldwide. In 2009 asthma caused 250,000 deaths globally. Asthma is characterized by recurrent episodes of wheezing, shortness of breath, chest tightness and coughing. Symptoms are often worse at night and in the early morning, or in response to exercise or cold air. Some people with asthma only rarely experience symptoms, usually in response to triggers, whereas other may have marked persistent airflow obstruction. A number of other health conditions occur more frequently in those with asthma including: gastro-esophageal reflux disease, rhino sinusitis, and obstructive sleep apnea. Psychological disorders are also more common. Asthma is caused by environmental and genetic factors. These factors influence how severe asthma is and how well it responds to medication. The interaction is complex and not fully understood. It is believed that the recent increased rates of asthma over are due to epigenetic or...
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