Asthma is a disease of the airways in the lungs. Its symptoms are caused by inflammation, which makes the airways red, swollen, narrower and extra-sensitive to irritants. This leads to recurrent attacks of wheezing, breathlessness, chest tightness and coughing. Mild attacks can settle down without treatment, but treatment usually helps them to resolve more quickly. Appropriate treatment can also reduce the risk of further attacks. If you experience a serious attack you should seek emergency help.

Asthma is a long-term (chronic) disease. Your asthma does not stay the same, but changes over time, and every person with asthma has good and bad days (or longer periods of time).

Asthma is very common. Around one out of every ten people in the Western World develops asthma at some stage in their life.

Asthma tends to run in families, which means that you are more likely to develop asthma if someone in your family already has it. Children with eczema or food allergy are more likely than other children to develop asthma.

Allergy to pollen, house dust mites or pets also increases your chance of developing asthma. Exposure to tobacco smoke, air pollution or other inhaled irritants can also cause asthma symptoms in those with an underlying tendency to asthma.