Bronchial asthma, named after the Greek word for breathlessness and panting, is an inflammatory disease of the lungs. The wheezing, coughing and gasping to get air through the narrowed airways is the result of inflammation an damage which makes the airways hyper-responsive. Cells in the airways are triggered to release chemical factors that ultimately cause the airways to become inflamed and infiltrated with special types of white blood cells. In chronic severe asthma, the epithelial lining of the airways is progressively destroyed, leaving them hyper-responsive and susceptible to severe spasm at the slightest provocation. This may be from an allergen, such as house dust or animal fur, or simply through exercise, breathing cold air or the night-time occurrence of broncho-constriction.
Asthma has increasingly been seen as a problem of inflammation. Researchers agree that allergy, infection, and irritating pollutants can individually and synergistically worsen the condition. Allergy may play a larger role in the observed increase in asthma prevalence worldwide.
Three major factors-familial, allergenic, and environmental-underlie asthma. Asthma is largely a case of inherited susceptibility. Children with one parent with asthma have about a 25% chance of being asthmatic while those with two asthmatic parents have about a 50% chance. Air pollution can act upon this susceptibility to irritate, poison, or change the immune responsiveness of cells.