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.

Asthma is usually caused by a mixture of hereditary factors (those you are born with) and environmental factors. However these factors working together is still largely unknown. Allergens from house dust mites and pets are the most common causes, but many other allergens, such as pollen and molds, can cause asthma.

When you use your inhaler without a spacer, the majority of the medication goes into your mouth or stomach rather than your lungs, where it is most effective. The medicine sits in a fine mist in the holding chamber of the spacer, which you can then inhale slowly.

Spacer is a device that attaches to the inhaler.

Medicine slowly flows through your pathways rather than immediately distributing to the mouth.