Asthma is a chronic condition in your lungs that has two main components. When you have asthma, two things happen inside your lungs --- constriction, the tightening of the muscles surrounding the airways, and inflammation, the swelling and irritation of the airways. Constriction and inflammation cause narrowing of the airways, which may result in symptoms such as wheezing, coughing, chest tightness, or shortness of breath. Furthermore, there is increasing evidence that, if left untreated, asthma can cause long-term loss of lung function.

When you have asthma and are exposed to a trigger, the airways leading to the lungs become more inflamed or swollen than usual, making it harder for you to breathe. The airways also get smaller due to a tightening of the muscles surrounding the airways, and they get "stuffed up" due to a build-up of mucus.

Several triggers can cause your asthma symptoms to flare up, and may include allergies, infections, and strong odors or fumes that you may come in contact with at your home or office. Once you are exposed to a trigger and have a reaction, your airways also become more sensitive to other triggers. So, it's important to manage your asthma every day. Airway inflammation may always be there --- even when you are not having a lot of symptoms.