The relationship between tobacco smoke & bronchial asthma.

Bronchial asthma is a common disease and an important cause of morbidity among both children and adults. Tobacco smoking, both active and passive i.e., exposure to environmental tobacco smoke (ETS) has got important effects on asthma. Smoking by adults causes bronchial irritation and precipitates acute episodes. It also increases bronchial responsiveness and causes airway sensitization to several occupational allergens. Smoking may also increase the disease severity. Continued smoking by adult asthmatics is the likely cause of irreversibility of airway obstruction and development of chronic obstructive pulmonary disease. ETS exposure affects asthma in a similar fashion. Parental smoking is commonly associated with increased asthma symptoms, respiratory infections, acute episodes and frequent hospitalization of children. Bronchial responsiveness and airway sensitization may also increase. Childhood exposure to smoking is also considered as a risk factor for the development of asthma. Similarly, in utero exposure to maternal smoking may be independently responsible for early onset asthma. ETS exposure in adult asthmatics from smoking by spouses, siblings or colleagues is equally troublesome. There is increased morbidity and poorer asthma control. Asthmatic symptoms sharply decline after the ETS exposure is reduced.