Asthma is a common chronic inflammatory condition affecting the airways and displays a varied phenotypic picture. It is becoming increasingly recognized by healthcare workers and epidemiological studies suggest that along with other atopic diseases, its prevalence is rising. The precise etiology of asthma remains uncertain, but genetic and environmental factors such as viruses, country of origin, allergen exposure, early use of antibiotics, and numbers of siblings have all been implicated in its inception and development. Pathologically it is characterized by inflammation, physiologically by...