For people who have asthma that is well controlled, changing altitude will probably not have any noticeable effect on asthma symptoms. But for people whose are sensitive to the mold Aspergillus fumigatus (A. fumigatus), spending time at a higher altitude may actually improve asthma symptoms.
Asthma is a chronic condition that makes breathing difficult. During an asthma attack, the lining of the airways becomes inflamed and swollen, and starts producing excess mucus. At the same time, the muscles surrounding the airways can tighten, which constricts the airways. All these factors combine to make it harder for air to move in and out of the lungs.
A. fumigatus is a fungus that commonly grows on dead leaves, on other decaying plants, and in soil. When the soil is disturbed, the spores can become airborne. Because of their small size they can easily be inhaled all the way into the alveoli (tiny air sacs) in the lungs. A. fumigatus is so common that scientists believe all people will inhale at least several hundred spores every day. (National Center for Biotechnology Information)
People who have healthy immune systems are typically able to get rid of the spores without becoming sick. But people whose immune systems are not healthy, such as those with cancer or leukemia, are more likely to develop a serious lung infection when they inhale the spores. Modern immunosuppressant therapies for various diseases such as organ transplants have also made more people susceptible to infection from these spores. This fungal infection can create abscesses in healthy lung tissue or can accumulate and grow in existing cavities in the lungs caused by other diseases. In severe cases, the infection can be fatal.
A group of Dutch researchers studied 170 patients who had severe asthma that was not under control at sea level. Some of the patients had a known sensitivity to A. fumigatus and some did not. The researchers took the group to the Dutch Asthma Centre Davos in Switzerland, which is located at an altitude of approximately 5,250 feet. The area is also known for its dry climate and low air pollution.