What causes asthma?

What causes asthma?

Researchers don’t know why some people have asthma while others don’t. But certain factors present a higher risk:

• Allergies: Having allergies can raise your risk of developing asthma.
• Environmental factors: People can develop asthma after exposure to things that irritate the airways. These substances include allergens, toxins, fumes and second- or third-hand smoke. These can be especially harmful to infants and young children whose immune systems haven’t finished developing.
• Genetics: If your family has a history of asthma or allergic diseases, you have a higher risk of developing the disease.
• Respiratory infections: Certain respiratory infections, such as respiratory syncytial virus (RSV), can damage young children’s developing lungs.