Asthma in Teens and Adults - Cause
The cause of asthma isn't known. Health experts believe that inherited, environmental, and immune system factors combine to cause inflammation of the airways. This can lead to asthma and asthma attacks.
Asthma may run in families (be inherited). If this is the case in your family, you may be more likely than other people to get long-lasting (chronic) inflammation in the airways.
In some people, an allergic reaction causes asthma symptoms. An allergen makes the immune system cells release chemicals that cause inflammation.
Studies show that exposure to allergens such as dust mites, cockroaches, and animal dander may influence asthma's development. Asthma is much more common in people who have allergies. But not all people who have allergies get asthma. And not all those who have asthma have allergies.
Environmental factors and today's germ-conscious lifestyle may play a role in the development of asthma. Some experts believe that there are more cases of asthma because of pollution and less exposure to certain types of bacteria or infections.1 As a result, children's immune systems may develop in a way that makes it more likely they will also get allergies and asthma.
Asthma in adults also can be related to exposure to substances at work. This is called occupational asthma.