Asthma is a chronic (lifetime) disease that makes your lungs very sensitive and hard to breathe. Asthma can’t be cured, but with proper treatment, people with asthma can lead normal active lives.
If you have asthma, your airways (breathing passages) are very sensitive. Certain things can make your airways become:
Swollen and filled with mucus – the swelling and mucus makes your airways narrower, so it is hard for air to pass through
Small and tight – your airways might also become twitchy and squeeze together and tighten. This makes your airways narrower and hard for air to pass through.