How Asthma Works

Asthma is a complex disease that can affect the body in a number of ways. Understanding exactly what's going on is essential to creating a plan for controlling the disease. At UI Health, our team of asthma doctors have the experience to help you manage your asthma and live your best possible life despite the disease.

We'll work carefully to identify how asthma is affecting your body and to prescribe the best possible course of treatment.

Here are some of the things we look for and address when we evaluate how best to control your asthma.


The most important thing to know about how asthma works is that it is a disease of inflammation. All of the other components of asthma stem from that central problem. Inflammation is a common process throughout the body. There are times, though, when the standard bodily process of inflammation gets out of hand, resulting in an inflammatory disease, such as asthma.

In asthma, inflammation happens in the airways. Even when a person with asthma is not having an asthma attack and seems to be breathing OK, the walls of his or her airways remain inflamed. They are swollen and produce too much mucus, dramatically shrinking the space available for air to pass through. This is why medicines to reduce inflammation (especially inhaled corticosteroids) are at the center of most asthma treatment plans.

In addition to its direct effects, inflammation contributes to the other two major problems in asthma — airway hyperresponsiveness and excessive bronchoconstriction.

Airway Hyperresponsiveness

Physicians often refer to asthmatic airways as "twitchy" because they are terribly sensitive to things that would cause no noticeable effect on the airways of non-asthmatics. (The medical term for this "twitchiness" is hyperresponsiveness.) Just walking into cold air, or sitting near someone wearing perfume, for example, can trigger a big reaction in the airways of an asthmatic. The airway walls swell up even more, the airway muscles squeeze, and the person with asthma can find himself wheezing, coughing, and maybe even having trouble breathing at all.

Doctors have noted, however, that if the inflammation in an asthmatic person's airways is controlled by medicines, the airways become much less "twitchy."

Excessive Bronchoconstriction

Airways are hollow tubes made up of different layers of tissue, one of which is a layer of smooth muscle. In a person with asthma, the airway muscles tend to be particularly large and strong.

When a response of the airways is triggered, the muscles contract, squeezing the airway and narrowing the space that air can get through. The smooth muscle of the airway in a person with asthma contracts too easily, too hard, and too long. As the airways of asthmatics already can be swollen and partly filled with mucus, so the extra squeezing of the airway smooth muscle can make it difficult or even impossible for air to get through.

Excessive contraction of airway muscle appears to be directly related to airway inflammation. Controlling the inflammation with anti-inflammatory medicines helps prevent the muscles squeezing so easily and so hard, and thus, helps prevent asthma episodes.

"Rescue" or "reliever" medicines (such as albuterol, Ventolin, and Proventil) work by making the airway's smooth muscle relax, to temporarily stop them from squeezing the airway closed, but they do not treat the inflammation at the root of the problem.

Get Help Managing Your Asthma

To make an appointment with an asthma doctor, please fill out the online form or call 312.996.3300.