Asthma has no single, easily identified cause. Multiple Asthma has no causes and the interaction of several factors may be single, easily necessary to cause the disease. Studies have implicated identified a familial component. The tendency to develop asthma cause has an inherited basis. If one or both parents have asthma, for example, their child has a greater likelihood of developing asthma, as compared to another child whose parents have no personal history of asthma.
Similarly, studies of large populations of twins, comparing asthma and allergy in pairs of identical and fraternal twins, point to an inherited factor required for asthma development. The actual mode of inheritance is not known. Researchers around the world are working to identify a chromosomal basis for asthma. Investigation into different genes on certain chromosomes has yielded interesting results, but an “asthma gene” has yet to be discovered. Advances in molecular biology will hopefully lead not only to the identification of primary asthma genes, but also to the genes responsible for disease severity (asthma severity-modifying genes), as well as for response to standard treatments (asthma treatment-modifying genes).
Clinicians have long noted that certain viral infections seem to be related to the development of asthma in predisposed individuals. Physicians for example describe “asthmagenic” viruses that cause typical respiratory infection and symptoms at first, only to leave the patient with an asthma-like condition. Asthma often goes hand-in-hand with allergies, especially in children and teens. Asthma is more common in persons with atopy, allergic rhinitis, and eczema. Some types of asthma, called occupational asthma, are related to specific industrial settings and exposures.
The above observations, along with a large body of research findings, have lead to the current view that asthma is probably “caused” by a complex interaction between a “susceptible” individual and certain environmental conditions.
It’s especially important to remember that asthma is tricky: changing weather conditions, humidity holding particles in the air, smoke, and volatile organic compounds all can produce asthma symptoms. In the city where renovations, construction, street repair, cleaning heating systems, and blowing stacks can occur at any time, its important to keep a sharp eye (ear and nose, as well) on the ever-modifying environment.
Possible Environmental Factors in Asthma Development
The development of asthma reflects a particular genetic or innate predisposition to the disease. In addition, environmental influences have been recognized as significant in the emergence of clinical asthma. The precise interplay between environmental and hereditary factors leading to asthma is still insufficiently understood. It is has long been noted that that some environmental exposures are associated with progression to asthma while other types of exposure might possibly prevent or delay the development of asthma in susceptible persons. The complex relationships are the subject of ongoing research, at the molecular level, in laboratory animals, and in human populations.