Asthma - Picture Summary

This leaflet gives a brief summary of asthma.

We are holding off reviewing this leaflet until the SIGN guidelines on asthma are published, due October 2014.

See separate leaflet called Asthma for more detailed information.

Asthma diagram
  • Asthma is caused by inflammation in the airways. The cause of the inflammation is not known. The inflammation causes the muscle in the airways to contract, and also extra mucus to form. These make the airways narrower than normal.
  • Symptoms include: wheeze, cough, and shortness of breath. Symptoms can range from mild to severe.
  • Certain 'triggers' make symptoms worse in some people. For example, exercise, colds, pollen, allergy to pets, air pollution.
  • Most people with asthma are treated with inhalers.
    • Reliever inhalers relax the muscle in the airways. This gives quick relief of symptoms as the airways open wider. These are also known as 'bronchodilator' inhalers as they dilate (widen) the airways (the bronchi). You use these inhalers 'as required' if symptoms develop.
    • Preventer inhalers reduce inflammation. The drug in most preventer inhalers is a steroid. Use these each day to prevent symptoms from occurring.
    • Long acting bronchodilator inhalers work in a similar way to 'relievers', but work for up to 12 hours after taking each dose. One may be needed if symptoms are not fully prevented by the preventer inhaler alone. (Some brands of inhaler contain a steroid plus a long acting bronchodilator for convenience.)
  • Most people with asthma should take a regular preventer inhaler. The aim is to prevent symptoms so that you can get on with a normal life.
  • You may need a short course of steroid tablets now and then to treat a bad attack of asthma. Steroids reduce inflammation.
  • You should not smoke.
  • Make sure you know:
    • how to take your inhalers.
    • which is your reliever inhaler, and which is your preventer inhaler.
    • what to do if symptoms get worse.

See also separate leaflets on Asthma, Asthma - Peak Flow Meter, Asthma - Peak Flow Diary and Inhalers for Asthma.

Further help & information

Original Author:
Dr Tim Kenny
Current Version:
Document ID:
4591 (v42)
Last Checked:
Next Review:
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