Asthma Basics

Asthma Basics
What is asthma?


Asthma is a condition that affects the airways – the small tubes that carry air in and out of the lungs.


When a person with asthma comes into contact with something that irritates their airways (an asthma trigger), the muscles around the walls of the airways tighten so that the airways become narrower and the lining of the airways becomes inflamed and starts to swell. Sometimes sticky mucus or phlegm builds up which can further narrow the airways. The illustration on the right shows a cross section of the airways, with and without inflammation.

All these reactions cause the airways to become narrower and irritated - making it difficult to breath and leading to symptoms of asthma.

What causes asthma?


It is difficult to say for sure what causes asthma.
What we do know is that:

* you are more likely to develop asthma if you have a family history of asthma, eczema or allergies
* it is likely that this family history combined with certain environmental factors influences whether or not someone develops asthma
* many aspects of modern lifestyles – such as changes in housing and diet and a more hygienic environment – may have contributed to the rise in asthma over the last few decades
* research has shown that smoking during pregnancy significantly increases the risk of a child developing asthma
* children whose parents smoke are more likely to develop asthma
* environmental pollution can make asthma symptoms worse and may play a part in causing some asthma
* adult onset asthma may develop after a viral infection
* irritants found in the workplace may lead to a person developing asthma (occupational asthma).

Asthma symptoms

The usual symptoms of asthma are: :

* coughing
* wheezing
* shortness of breath
* tightness in the chest.


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