What is bronchial asthma?

Bronchial asthma is a common lung disease affecting millions of people worldwide. Like COPD, it is characterised by narrowing of the airways (bronchioles) in the lungs, but there are some major differences. First, bronchial asthma is an allergic reaction to certain particles in the air, known by the general term allergens, which usually come from other animals or plants. Examples of allergens include:

• Pollen from trees, crops and flowers
• House dust mites (microscopic crawling animals that live in house dust and feed on the flakes of skin that humans shed every day)
• Animal hairs (especially domestic animals like cats, dogs and horses)

The muscles in the walls of the bronchioles constrict (become narrow) if a person with asthma breathes in an allergen that he or she has become sensitive to. Most people are not sensitive to these common allergens, so people who develop bronchial asthma may have genetic factors that make their lungs react so strongly. The narrowing of the bronchioles can begin very suddenly and is called an asthma attack. The symptoms of an asthma attack are similar to COPD and include wheezing, coughing, chest tightness and shortness of breath. If the person uses an inhaler (a device that sprays special medicine into their lungs), the narrowing of the bronchioles can usually be reversed quite quickly, so they can breathe normally again.

However, you should always advise people who are having an asthma attack to be taken urgently to a hospital or health centre if the symptoms do not quickly improve. Although it is unusual for people in high-income countries to die from an asthma attack, this is because most patients carry inhalers with them everywhere and can treat themselves if an attack begins. In countries like Ethiopia, where very few people with asthma have an inhaler, a severe attack can leave the person so short of breath that they die from lack of oxygen.

The factors that set off and worsen acute asthma symptoms are called 'inducing factors'. They include smoke, atmospheric pollution, some chemicals, and bacterial and viral infections, etc. It is also believed that emotional stress and worry are inducing factors for an asthma attack. Identifying and avoiding asthma-inducing factors are essential steps in preventing a person with asthma from developing an attack of symptoms.

The effects of asthma on people's lives has some common features with COPD, such as breathlessness restricting physical and social activities. People with asthma are often anxious about the sudden onset of an attack and they may try to avoid going to places where they may be exposed to an inducing factor or an allergen.

In the next study session, we turn to chronic conditions affecting vision and hearing.