An asthma attack is when, after a period of time when aperson has had only a few or no symptoms of asthma, the asthma gets worse all of a sudden, usually because of being exposed to one or more triggers. When the asthma attack happens, the tissue inside the airways swell because of "inflammation" - which is how the body tries to protect itself from harmful things, like germs and irritants. When the tissues swell the opening (called the "lumen") in the airway gets very narrow.