I found this Mayo Clinic article very interesting:
Vocal cord dysfunction: Is it a type of asthma?
What's the difference between vocal cord dysfunction and asthma?
from James T C Li, M.D., Ph.D.
Both asthma and vocal cord dysfunction can make breathing difficult. Signs and symptoms of either condition can include coughing, wheezing, throat tightness and hoarseness, but they're two separate disorders.
Vocal cord dysfunction is the abnormal closing of the vocal cords when you breathe in or out. It's also called laryngeal dysfunction or paradoxical vocal cord motion. As with asthma, breathing in lung irritants, having an upper respiratory infection or exercising may trigger vocal cord dysfunction symptoms. However, unlike asthma, vocal cord dysfunction isn't an immune system reaction and doesn't involve the lower airways. Treatment for the two conditions also is different.
Your doctor may suspect vocal cord dysfunction rather than asthma if:
It's harder to breathe in than breathe out when symptoms flare up
Asthma medications don't seem to ease your symptoms
Results of breathing (pulmonary function) tests or other tests for asthma are normal
Your symptoms are not due to a respiratory infection alone, something in your airways or another health problem.
Because they have similar triggers and symptoms, it's common for vocal cord dysfunction to be misdiagnosed as asthma. This can lead to use of asthma medications that don't help and cause side effects. Some people have both vocal cord dysfunction and asthma, and require treatment for both conditions.