Asthma is a chronic disease characterized by recurrent attacks of breathlessness and wheezing, which vary in severity and frequency from person to person. Symptoms may occur several times in a day or week in affected individuals, and for some people become worse during physical activity or at night.
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)
- Tobacco smoke
- Chemical irritants in the workplace
- Air pollution
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-steroidanti-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.
Although asthma cannot be cured, appropriate management can control the disease and enable people to enjoy good quality of life.
Short-term medications are used to relieve symptoms. People with persistent symptoms must take long-term medication daily to control the underlying inflammation and prevent symptoms and exacerbations.
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.
According to World Health Organization (WHO) estimates 235 million people worldwide suffer from asthma. Asthma is the most common chronic disease among children. Asthma is not just a public health problem for high income countries: it occurs in all countries regardless of level of development. Over 80% of asthma deaths occurs in low- and lower-middle income countries.
Asthma is under-diagnosed and under-treated, creating a substantial burden to individuals and families and possibly restricting individuals’ activities for a lifetime.