As you get older, it becomes more difficult to separate asthma from other wheezing conditions and a doctor may have to do special testing to make this distinction. Frankly, our understanding of who will develop asthma is limited. We know that the tendency toward asthma is, in part, inherited and that you are more likely to suffer from this condition if your mother has asthma than if your father has asthma. There are research studies suggesting that exposure to cigarette smoke either while the baby is developing in the mother's womb or in the first few years of life can lead to asthma. In addition to an inherited predisposition, exposure to certain allergens or infections with some viruses appears to promote the development of asthma.
Many people have asthmatic attacks when they are exposed to allergens.
For example, it is common to suffer an attack when visiting someone who has a cat or a dog, if you are allergic to these animals. Asthma may also be brought on in an otherwise apparently healthy person by infection with certain viruses. These individuals develop asthmatic symptoms such as shortness of breath, cough, and wheezing during the recovery phase of the virus. Finally, many asthma patients have an attack during or shortly after exercise. This may be more common while exercising in cold, dry conditions or if the air being breathed in contains substances to which the patient is allergic.