In asthma, the bronchial tubes, mucus membranes, and mucus glands react abnormally to stimuli. Bronchial muscles clamp down around the bronchial tubes, causing a condition known as broncho-spasm. The mucus membranes inside the tubes become inflamed and swollen, further narrowing the air channels. The bronchial glands start producing large amounts of a particularly thick and sticky mucus that is hard to cough up and often forms plugs that further obstruct airflow. As a result of these changes, not enough oxygen can get into the body, and air loaded with carbon dioxide is trapped inside the lungs' air sacs.
Asthmatics have to fight to exhale.
Coughing is another important symptom, especially in very young children. Scratching the neck or chest or yawning a great deal should alert concerned parents that an attack is on the way. Shortness of breath, spitting up mucus, a pale, sweaty face, and a tight chest are other symptoms. When the attack is severe, wheezing sometimes disappears because the smaller airways are completely blocked, a dangerous stage. An asthma episode can last for hours or days, occur once in a lifetime, or every day.