哮喘 is an illness that affects the airways of the lungs. It is also called reactive airway disease.

哮喘 symptoms are from three typical changes that occur in the airways:

• Swelling of the lining of the airways is the most common feature of asthma. Most people who have asthma have some degree of swelling of their lungs lining all the time.
• Increase response of the airways is another common feature of asthma. When the airways become responsive, they react when exposed to things 被称为触发器. Triggers are things that make asthma worse.
• Blockage of airflow in the airways causes tightening of the muscles that surround the airways.

All these changes result in recurring acute episodes or attacks of breathing. When this happens, you may have coughing, wheezing, chest tightness, and shortness of breath.

The exposure to certain stimuli, 被称为触发器, create more swelling of the airways, which blocks the movement of air in and out of the lungs.

哮喘 flare-ups can range from mild, moderate or severe. Sometimes the symptoms are life threatening. All people with asthma should be under a doctor's care to manage their disease, to keep it under control and to keep them healthy.