Management of asthma: the essentials of good clinical practice.

Asthma is a condition that affects all countries worldwide. It is a chronic, disabling condition that diminishes the quality of life and the economic prosperity of those who live with it. The majority of persons living with asthma are from developing countries. Asthma management necessitates long-term treatment that is expensive, making it less accessible to poor people. The cost of medications is the key factor preventing people living with asthma from having access to care that has the potential to relieve their suffering, improve their quality of life and enhance their economic status. Asthma is a disease caused by environmental exposures. Genetic factors predispose certain people to developing asthma once they are exposed to the causative agents, and certain factors can trigger symptomatic episodes of asthma in those who have already developed the disease. Certain clinical characteristics differentiate asthma from other chronic lung conditions. The most important of these is that the symptoms and functional disability caused by asthma vary from one occasion to another. In those with less severe asthma, they may be present on some occasions and not others; in those with more severe asthma, their degree of severity varies from one time to another.