clipped from en.wikipedia.org

Asthma

Asthma is a chronic condition (generally associated with humans but also controversially being diagnosed in housepets such as cats^[1]) involving the respiratory system in which the airway occasionally constricts, becomes inflamed, and is lined with excessive amounts of mucus, often in response to one or more triggers.^[2] These episodes may be triggered by such things as exposure to an environmental stimulant (or allergen) such as cold air, warm air, perfume,^[3] moist air, exercise or exertion, or emotional stress. In children, the most common triggers are viral illnesses such as those that cause the common cold.^[4] This airway narrowing causes symptoms such as wheezing, shortness of breath, chest tightness, and coughing. The airway constriction responds to bronchodilators. Between episodes, most patients feel well but can have mild symptoms and they may remain short of breath after exercise for longer periods of time than the unaffected individual.