Asthma is a chronic disease characterized by recurrent attacks of breathlessness and wheezing, which vary in severity and frequency from person to person. During an asthma attack, the lining of the bronchial tubes swells, causing the airways to narrow and reducing the flow of air into and out of the lungs.
The causes of asthma are not completely understood. However, risk factors for developing asthma include inhaling asthma “triggers”, such as allergens, tobacco smoke and chemical irritants. Asthma cannot be cured, but appropriate management can control the disorder and enable people to enjoy a good quality of life.
During an asthma attack, the lining of the bronchial tubes swell, causing the airways to narrow and reducing the flow of air into and out of the lungs. Recurrent asthma symptoms frequently cause sleeplessness, daytime fatigue, reduced activity levels and
school and work absenteeism. Asthma has a relatively low fatality rate compared to other chronic diseases.
The fundamental causes of asthma are not completely understood. The strongest risk factors for developing asthma are a combination of genetic predisposition with environmental exposure to inhaled substances and particles that may provoke allergic reactions or irritate the airways, such as:
indoor allergens (for example, house dust mites in bedding, carpets and stuffed furniture, pollution and pet dander)
outdoor allergens (such as pollens and moulds)
chemical irritants in the workplace
Other triggers can include cold air, extreme emotional arousal such as anger or fear, and physical exercise. Even certain medications can trigger asthma: aspirin and other non-steroid anti-inflammatory drugs, and beta-blockers (which are used to treat high blood pressure, heart conditions and migraine).
Urbanization has been associated with an increase in asthma. But the exact nature of this relationship is unclear.
Reducing the asthma burden
Although asthma cannot be cured, appropriate management can control the disease and enable people to enjoy a good quality of life. Short-term medications are used to relieve symptoms. Medications such as long-term inhaled steroids are needed to control the progression of severe asthma.
People with persistent symptoms must take long-term medication daily to control the underlying inflammation and prevent symptoms and exacerbations. Inadequate access to medicines is one of the important reasons for the poor control of asthma in many settings.
Medication is not the only way to control asthma. It is also important to avoid asthma triggers - stimuli that irritate and inflame the airways. With medical support, each asthma patient must learn what triggers he or she should avoid.
Although asthma does not kill on the scale of chronic obstructive pulmonary disease (COPD) or other chronic diseases, failure to use appropriate medications or to adhere to treatment can lead to death.