Asthma symptoms affect an estimated 26 million Americans and are one of the leading causes of absences from work and school. Although asthma has no cure, effective treatments are available; the condition can be best managed by seeing an allergist. Learn about how asthma can affect children and pregnancies.
Find an allergist
What causes asthma?
Asthma is a chronic inflammation and obstruction of the bronchial tubes, the airways that allow air to enter and leave the lungs. People often think of asthma in terms of episodes or attacks. Actually, someone with asthma always has it, but the symptoms may not appear until triggered by something that provokes a response in the body, such as exercise, cold air, stress, illness, irritants in the air, certain medications or an allergen.
Allergens are substances that cause no problem in most people but produce an abnormal reaction in some. When someone who is sensitive to an allergen is exposed to it, his or her immune system “sees” it as a foreign substance and releases chemicals to deal with it. For people with asthma, those chemicals can cause an asthma attack — meaning that their airways become constricted, they find it difficult to breathe and they may experience coughing or wheezing.