Asthma is a common disorder in which chronic inflammation of the bronchial tubes (bronchi) makes them swell, narrowing the airways. Asthma involves only the bronchial tubes and does not affect the air sacs (alveoli) or the lung tissue (the parenchyma of the lung) itself.

 

Airway narrowing in asthma is due to three major processes acting on the bronchi: inflammation (see above), spasm (bronchospasm), and hyperreactivity (over-reaction of the bronchi to factors that can precipitate asthma).

 

The incidence of asthma has risen dramatically in the past 20 years, a period far too short to reflect any significant changes in the gene pool. This supports the important role that environmental influences (allergy, infection, lifestyle, and diet) have on the development of asthma.

Many environmental factors are known to precipitate attacks of asthma. These factors are all either allergens or irritants. Allergic factors play a role in many, but by no means every, case of asthma.

Signs and symptoms include shortness of breath, chest tightness, cough and wheezing. The diagnosis is based on these features (without wheezing, it is not asthma) and is confirmed with breathing tests. Chest X-rays are usually normal in people with asthma.

As a rule, the bronchial narrowing characteristic of asthma can be partially or completely prevented or reversed with proper treatment. Avoiding precipitating factors is important in managing asthma.

 

Medication at School Form (Must be Completed)