Researchers have not been able to determine why one person gets asthma and another doesn’t. There are factors that create a higher risk:   If you have allergies, that puts you at a higher risk of developing asthma.   The environmental factors that expose people to things that irritate their airways increase the risk of asthma. Things like allergens, fumes, smoke and toxins are all connected to asthma. These are especially harmful to infants and young children.   Genetics plays a role in who develops asthma. A family history of allergies and asthma put people at a higher risk.   Certain respiratory infections, like respiratory syncytial virus (RSV) can do damage to young children’s developing lungs.