Experts have known for some time that severe persistent asthma is much more difficult to bring under control, control being the main goal of asthma treatment. People with severe asthma often respond much less positively to treatment. Because of this, the Severe Asthma Reseach Program (SARP for short) conducted a multi-center study to try and find out why.

Ultimately, the study findings suggested that severe asthma may actually be a whole different type of asthma from the mild to moderate forms. In fact, the dysfunction that occurs in the airways is different. Here’s how:

• Airflow limitation. All asthmatics experience a narrowing of the airways in response to asthma triggers. Airways may even close completely in a severe asthma attack. They also fill with mucus. This narrowing results in the symptoms of asthma, such as wheezing and difficulty breathing.
• Air trapping. Most asthmatics will be able to empty their lungs during an exhalation at least 70% or so. But in people who have severe asthma, exhalation fails to empty to even that level and air gets trapped in the airways.
• Reversibility. One of the hallmarks of asthma that is used as a diagnostic tool, is that the asthma symptoms are reversible with a bronchodilator (a quick-relief inhaler, for example). In severe asthma, symptoms do not always responds adequately to a bronchodilator.
• Hyperresponsiveness. All people who have asthma tend to be extremely sensitive to airborne irritants, such as smoke or fumes. These irritants can cause the airways to close up.

Researchers say that improving our understanding of the underlying causes at work with severe asthma may suggest new and more effective treatment approaches.

Learn More:

• Overview of classifications of asthma
• Asthma treament approaches

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