Asthma Causes
What Causes Asthma?
A combination of factors (family genes and certain environmental exposures) interact to cause asthma to develop, most often early in life. These factors include:
- An inherited tendency to develop allergies, called atopy
- Certain respiratory infections during childhood
- Contact with some airborne allergens or exposure to some viral infections in infancy or in early childhood when the immune system is developing
If asthma or atopy runs in your family, exposure to airborne allergens (for example, house dust mites, cockroaches, and possibly cat or dog dander) and irritants (for example, tobacco smoke) may make your airways more reactive to substances in the air you breathe.
Different factors may be more likely to cause asthma in some people than in others.