Bronchospasm is a difficulty in breathing caused by a sudden constriction of the muscles in the walls of the bronchioles. It is caused by the release (degranulation ) of substances from mast cells or basophils under the influence of anaphylatoxins.
Bronchospasm appears as the feature of asthma, chronic bronchitis and anaphylaxis. The overactivity of the bronchioles' muscle is a result of exposure to a stimulus which under normal circumstances would cause little or no response. The resulting constriction and inflammation causes a narrowing of the airways and an increase in mucous production; this reduces the amount of oxygen that is available to the individual causing breathlessness, coughing and hypoxia (that can cause cyanosis).