What are the characteristics of asthma?
Obstruction of the lower respiratory tract that is partially or completely reversible, either spontaneously or with bronchodilator or anti-inflammatory treatment.
Chronic inflammation of the respiratory tract.
Increased reactivity of the respiratory tract to various stimuli, such as air, cold or exercise in the natural environment and methacholine or inhaled histamine in a laboratory environment, with recurrent episodes of wheezing, coughing and dyspnea.