Someone with asthma can have trouble breathing because of problems with the airways, the tubes that carry air into the lungs. The airways can get irritated, swollen (puffed up), and narrow (like a pinched straw), which makes it difficult to breathe. Many things can trigger an asthma attack, like viruses, allergies, smoke, and even exercise. Of course, breathing is really important, so someone who has asthma may need to see a doctor regularly and carry special medicine to make it easier to breathe.
© 1995-2015 KidsHealth® All rights reserved. Images provided by iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart.com