Asthma

Asthma is a disease characterized by recurrent attacks of breathlessness and wheezing, which vary in severity and frequency from person to person. This condition is caused by the inflammation of the air passages in the lungs. It affects the sensitivity of the nerve endings in the airways so that they become easily irritated. In an attack, the lining of the passages swells, causing the airways to narrow and reducing the flow of air in and out of the lungs.

Although asthma is a chronic obstructive condition, it is not considered a part of COPD as this refers specifically to combinations of bronchiectasis, chronic bronchitis, and emphysema. Unlike these diseases, the airway obstruction in asthma is usually reversible. However, if left untreated, asthma can result in chronic inflammation of the lungs and irreversible obstruction. In contrast to emphysema, asthma affects the bronchi, not the alveoli. Public attention in the developed world has increased recently because of its rapidly increasing prevalence, affecting up to a quarter of urban children.

The strongest risk factors for developing asthma are a person’s exposure to allergens and a family history of asthma or allergy. Exposure to tobacco smoke and exposure to chemical irritants in the workplace are additional risk factors. Workplace conditions, such as exposure to fumes, gases or dust, are responsible for 11% of asthma cases worldwide.