Asthma is a chronic condition of the bronchioles, or small airways, inside the lungs. Airways are passages through which air flows, providing oxygen - an essential ingredient in maintaining life in the body. Since we need oxygen to live, a lack of it can be very distressing and even dangerous.
The airways in a person who has asthma are oversensitive (allergic), and are irritated easily. The irritation causes the inside of the airway to become red and swollen (inflammation) and the muscles surrounding the airway walls tighten (bronchoconstriction). These two processes narrow the airway passages, making breathing very difficult at times.
Common triggers are: house dust mites, pollen, pets - e.g. cats, cigarette smoke, weather changes - e.g. drop in temperature, colds & flu, exercise, stress, perfume, some medications.