An asthma attack (or “episode”) occurs when something bothers the lung airways, and makes asthma symptoms worse than usual. The airways of the lungs are like tree branches, starting out with a big diameter in the throat and near the entrance to lungs but subdividing into numerous smaller tubes as they progress deeper into the lungs. Near the ends of these airways, the smallest branches (called bronchioles) end in cul-de-sacs called alveoli and this is where air is exchanged with the blood. When the airways become irritated, muscles that surround each bronchiole tighten, narrowing the pathway for air flow and making it difficult to get fresh air into the alveoli. Irritation of the airways also causes increased inflammation, which makes the bronchiole tissue swell and release mucus, making it even more difficult to get air into the lungs. When the airways become very narrow and inflamed like this, it results in the symptoms of an asthma attack: coughing, wheezing, chest tightness, and shortness of breath. Some people report that an asthma attack feels like trying to breathe though a very narrow straw.

Asthma attacks are not all the same. A mild attack may cause some discomfort and may resolve over time or go away after treatment with a fast-acting inhaler. A severe asthma attack can cause the airways to close to a point where there is not enough oxygen getting into the lungs to supply the body’s vital organs. A severe asthma attack is a medical emergency that can result in death without treatment.