Asthma is a clinical condition in which there occurs reversible airway obstruction due to airway hyper-sensitivity and is characterized by cough, difficulty in breathing, chest tightness and presence of a whistle like sound while breathing. Airway hyper-sensitivity is triggered by various factors which lead to acute erection of the airway.
What causes Asthma?
The causes of asthma is poorly defined and mainly due to combination of environmental and genetic factors.
Some theories suggest that asthma in early childhood is caused by decreed infections in early life which prevent the formation of proper immunity and lead to development of airway hyper-sensitivity.
Warm, humid, centrally heated homes favor multiplication of house dust mites and this may contribute to childhood asthma. Having a pet at home may also lead to development of asthma.
Deficiency of dietary components like Vitamin A, C, E, milk fat, and selenium may lead to development of asthma. Obesity may also act as a factor in it's development.
What happens in Asthma?
When an allergen is inhaled two responses occur in airway track. First one occurs immediately leading to obstruction of the track. This allergen rapidly interacts with mucosal mast cells by an IgE-dependent mechanism, resulting in the release of mediators such as histamine and the cysteinyl leukotrienes with resulting constriction of the track. This is followed by a late response in which explosion occurs in the track. This late response occurs about 5-6 hours later to the initial attack.
With the progress of the disease, remodeling of the airway occurs, leading to fibrosis of the airway wall, fixed narrowing of the airway and a reduced response to airway dilator medicine.
Symptoms of Asthma?
- Difficulty in breathing
- Chest tightness
- Whistling sound on breathing
These symptoms are worst in the early morning but sometimes in poorly controlled asthma, the symptoms tend to wake the person up from sleep at night making it all worse. Sometimes cough is the only symptom of asthma.
Occupational asthma is now the most common form of occupational respiratory disorder.