Asthma

is a condition of the lungs that can cause breathing difficulties.  It is caused by inflammation of the tubes that supply the lungs with air, which causes them to temporarily narrow.  The main symptoms of asthma are breathlessness, a tight chest, a wheezing sound when breathing and sometimes coughing.  If the symptoms get worse this is known as having an asthma attack.  Common triggers for asthma can include smoke and pollution, allergies to dust, pollen or animals, vigorous exercise and sometimes infections such as a common cold or a virus such as influenza.