Asthma is a chronic respiratory condition that affects the airways, causing them to become inflamed and narrowed, which makes it difficult to breathe. Asthma can range in severity from mild to severe and can be a lifelong condition. The exact cause of asthma is not known, but it is thought to be a combination of genetic and environmental factors. Asthma triggers can include allergies, respiratory infections, exercise, air pollution, and stress, among others. Symptoms of asthma can include:WheezingShortness of breathChest tightnessCoughing, especially at night or early in the morning.