Asthma
Asthma has no identifiable causes thus, it is regarded as idiopathic. While bronchitis has some specific set of causes, doctors aren't sure why some people contract asthma, while others don't, even when both these groups are leading a similar lifestyle. Assumptions are that, genetic factors, and environmental factors may be the contributing factors. Doctors have, however, been able to identify factors which may trigger an asthma attack. These are: