The easiest way to determine cough variant asthma is when a patient has a cough with airway hyperresponsiveness that improves with asthma calming therapy.
Cough variant asthma is defined as a patient who has a cough with airway hyperresponsiveness as the only symptom of asthma. To diagnose cough variant asthma, a person with a chronic cough must have airway hyperresponsiveness that is relieved by asthma treatment.
The absence of airway hyperresponsiveness precludes the diagnosis of cough variant asthma. However, a typical history of children with difficulty in lung function manipulation, viral respiratory infections and allergen exposure-induced symptoms that are evident at night and exacerbated by activity and cold wind stimulation, combined with effective anti-inflammatory therapy, can be used as a basis for the diagnosis.
Inhaled corticosteroid therapy is effective and is sometimes the only method of identifying cough variant asthma. This approach is not recommended because some chronic coughs (eosinophilic bronchitis) are effectively treated with inhaled corticosteroids even though they are not associated with physiologic abnormalities of asthma.