When symptoms of asthma, such as wheezing, coughing, or shortness of breath, become more severe, more frequent, or both, it's known as an asthma flare-up (also known as an asthma flare, attack, episode, or exacerbation). In a person with asthma, the airways are overly sensitive to certain things (such as allergies, viral infections, cold air, exercise, and smoke) that can "trigger," or bring on, an asthma flare-up.
