Asthma is an inflammatory disorder of the conducting airways. The airways becomes hyper responsive and constrict easily in response to a wide range of exogenous and endogenous stimuli (1).
Asthma is a common chronic respiratory disease affecting between 1-18% of the population in different countries.
- associated chronic inflammation leads to hyper responsive airways which constrict easily in response to a wide range of exogenous and endogenous stimuli leading to recurrent symptoms and variable airflow limitations (1,2)
- symptoms and airflow limitation may settle spontaneously or with medication
- these episodes may be absent for long period of time (weeks or months) at a time (2)
The International Consensus Report on the Diagnosis and Management of Asthma (Global Initiative for Asthma - GINA) has put forward the following definition for asthma:“Asthma is a heterogeneous disease, usually characterized by chronic airway inflammation. It is defined by the history of respiratory symptoms such as wheeze, shortness of breath, chest tightness and cough that vary over time and in intensity, together with variable expiratory airflow limitation” (2).
Pathologically there is bronchial inflammation with a prominent eosinophilic infiltrate.
Asthma is common particularly in developed countries where up to 10% of children have the disease.