Video: asthma animation

Asthma is a chronic condition that can be managed but not cured. This animation explains asthma in detail

Asthma causes the airways of the lungs (the bronchi) to become inflamed and swollen.

The bronchi are small tubes that carry air in and out of your lungs. If you have asthma, the bronchi are more sensitive than normal and certain substances or triggers can irritate them.

Common triggers include house dust mites, animal fur, pollen, tobacco smoke, cold air and chest infections.

When the bronchi are irritated, they become narrow and the muscles around them tighten, which can increase the production of sticky mucus, or phlegm. This makes it difficult to breathe and causes wheezing and coughing, and it may make your chest feel tight.

The severity of the symptoms of asthma differs from person to person, from mild to severe. The narrowing of the airways is usually reversible – occurring naturally, or through the use of medicines. However, for some people with chronic (long-lasting) asthma, the inflammation may lead to an irreversible obstruction of the airways.

A severe onset of symptoms is known as an asthma attack, or 'acute asthma exacerbation'. Asthma attacks can be life-threatening and may require hospital treatment.


In 2005 in the UK, 1318 deaths were caused by asthma. Over 5m people in the UK have asthma. Asthma in adults is more common among women than men.

The cause of asthma is not fully understood, but it is thought to be a combination of genetic (inherited) and environmental factors. Asthma often runs in families, and you can inherit the susceptibility to asthma, which is then triggered by certain factors in the environment.

Factors include exposure to air pollutants, such as cigarette smoke, or certain substances that can cause allergic reactions (allergens), such as pollen or animal fur.

There is no cure for asthma, but there are a number of treatments that can normally manage the condition. Treatment is based on two important goals:

  • Relief of symptoms.
  • Preventing future symptoms from developing.

Successful prevention can be achieved through a combination of medicines, lifestyle advice and identifying and then avoiding potential asthma triggers.

There are also different types of pre-existing asthma that can be made worse by certain activities:

Work-aggravated asthma is a pre-existing asthma that is made worse by dust and fumes at work.

Occupational asthma is due to exposure to specific substances at work. Often these substances are specific to certain occupations. For example, some nurses develop occupational asthma as a response to prolonged exposure to latex, and some workers in the food-processing industry develop occupational asthma as a response to prolonged exposure to flour.

Exercise-induced asthma is a pre-existing asthma brought on by physical exercise. However, for most people it is an indication of poorly controlled asthma.

Last reviewed: 10/12/2007

Next review due: 09/12/2008


redmistpete said on 18 November 2009

I developed asthma shortly after working with mutagens. The military told me it was just a cat allergy.

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