Asthma is a common lung condition and affects an estimated 262 million people globally*. People with asthma can have normal, active lives when they learn to control their asthma. You can get asthma at any age. Asthma is not a contagious disease. Asthma is not caused by one single factor.
We do not fully understand what causes asthma, and there is no cure for it, but if you team up with your doctor and work out an asthma management plan that you are able to stick to every day, you can lead a healthy, fulfilling, active life. As you breathe, air moves in and out of your lungs through airways (breathing tubes). Airways get smaller and smaller like branches of a tree. Each airway has a fine inner lining called a mucous membrane.
Wrapped around the airways are muscle fibers that can constrict or relax to alter the size of the airways. The airways in people with asthma are more sensitive than usual, and easily become inflamed. Asthma is a condition of inflammation of the airways caused by certain triggers (listed below).
With exposure to these triggers, the lining of the airways swells and produces extra mucous, the muscles may tighten and the airways become narrower. This makes it difficult to breathe, and can result in coughing, wheezing, shortness of breath or the feeling of a tight chest.
This is known as asthma.
*Global burden of 369 diseases and injuries in 204 countries and territories, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019. Lancet. 2020;396(10258);1204-22