An asthma attack happens when the airways (bronchial tubes) in the lungs narrow. In asthma the airways are more sensitive than normal and when exposed to a "trigger" they overreact and become inflamed and narrow due to:

• Swelling of the airway lining
• Squeezing or spasm of the airway’s muscle walls
• Increased mucus

Asthma may be indicated by one or more of the following:

• cough -especially at night
• wheezing
• tightness in the chest
• shortness of breath

Certain triggers bring on asthma attacks in some people:

• allergy to house dust mite, pollens, moulds and pets
• irritants like cigarette smoke, dust or chemical fumes
• viral infections such as colds or flu
• vigorous exercise (medication may be needed before exercising)
• certain medicines such as aspirin and NSAIDS
• emotional stress or excitement
• cold air or a sudden temperature change
• some food additives