A group of lung and lower airway disorders characterized by wheezing, a high-pitched whistling sound. Causes of reactive airway disease include the chronic condition asthma, bronchial infections such as bronchiolitis and bronchitis, colds, congenital lung defects, a tumor, cystic fibrosis, inhalation of a foreign object, and pneumonia. Besides wheezing, other symptoms of reactive airway disease include chest tightness or pain, straining of chest muscles while breathing, and rapid breathing. In severe reactive airway disease, a lack of oxygen may cause the skin to grow bluish or gray.