Asthma is a chronic disease involving the respiratory system in which the airways become constricted, inflamed and lined with excessive mucous, often in response to one or more environmental triggers.

The incidence of asthma is increasing worldwide and has become much more common in affluent countries over the last few years. It is caused by a complex interaction of genetic and environmental factors that researchers do not fully understand as yet.

Asthma symptoms usually begin in early childhood, however asthma can present at any age, including in elderly persons. It is not generally considered a serious illness in most people who have it, mainly due to the mildness of symptoms and the range of very effective medicines.

Even so, asthma is one of the most common reasons for emergency department visits and hospitalization. Severe asthma attacks which may not be responsive to standard treatments are life threatening and may lead to respiratory failure and death.

Despite the severity of symptoms during an asthmatic episode, between attacks even severely asthmatic people may show few or even no signs of the disease.

Prevalence is greater in females after puberty and in the majority of adult onset cases diagnosed in persons over 40 years in females.
The incidence is increased in very young persons and the very old because of airway responsiveness and lower levels of lung function

Asthma often runs in families and you can inherit the susceptibility to Asthma, which is then triggered by certain factors in the environment.

Attacks are usually easily kept at bay with simple preventative measures and judicious use of bronchodilating inhalers.