external resources ICD - 10 J 45. ICD - 9 493 OMIM 600807 DiseasesDB 1006 MedlinePlus 000141 eMedicine med/177 emerg/43 MeSH C08.127.108 Asthma is a chronic disease of the respiratory system in which the airway occasionally constricts, becomes inflamed , and is lined with excessive amounts of mucus , often in