For people with cough-variant asthma, cough is the main—or only—asthma symptom.1 Children are more likely than adults to have this type of asthma.2 The cough is typically dry and unproductive, and it may be worse at night.
How is cough-variant different from classic asthma?
Cough-variant asthma has been described as a milder form of asthma.1 The risk of severe airway narrowing is lower with this type of asthma. In one small study, 30% of people with cough-variant developed classic within four years.3 In fact, the cough eventually went away for 16%.
In some ways, cough-variant asthma overlaps with allergic asthma. People with cough-variant are likely to have other allergic diseases, such as eczema, hay fever (allergic rhinitis), or food and drug allergies.4 Additionally, they usually have high levels of eosinophils, a type of white blood cell.1 The cough may be triggered by allergens, cold air, or exercise.
How is cough-variant asthma diagnosed?
There are many causes of chronic cough. Asthma is the cause in about 25% of cases.4 One challenge for health care providers is distinguishing between classic asthma, cough-variant, and bronchitis.1
Airway sensitivity is the main difference between asthma and bronchitis.1 People with asthma have “hyperresponsive” airways. This means that their airways are very sensitive and begin to close when triggered.
Airway sensitivity can be tested. The most common test is methacholine challenge. Spirometry is done to measure your lung function before and after inhaling a methacholine spray. If your airways start to close, you probably have asthma, rather than eosinophilic bronchitis.1
Spirometry without the methacholine challenge might not be a helpful test. Some people with cough-variant have normal lung function.2
How is it treated?
Treatment for cough-variant asthma follows the steps for long-term asthma management.
The first line of treatment for cough-variant is usually inhaled corticosteroids.1,5 If the cough improves with this medication, the diagnosis of cough-variant asthma is confirmed.5 Additionally, medications that open up the airways (bronchodilators) may be added if needed.4