Asthma and ICSs in patients with chronic cough

Asthma is thought to be one of the most common causes of chronic cough. After some basic diagnostic workup (spirometry, chest x-ray), is it reasonable to start a trial of inhaled corticosteroids in most patients? Or should each patient with suspected asthma undergo a bronchial provocation test or another specialist test?

Imran Satia: That is a very important question because you are right that asthma is regarded as one of the common triggers of chronic coughing. Many patients who come to the general practitioner may have symptoms of asthma, and many patients will get better with bronchodilators or low-dose inhaled corticosteroids. From a community setting perspective, I think, as a general practitioner, if you have a high index of suspicion of asthma, then it is completely reasonable to start a low-dose inhaled corticosteroid treatment. The only problem to be cautious of is that often the inhalation of the steroid inhaler sometimes can trigger and provoke coughing. Many patients may struggle to take or comply with the inhaled therapy for 6 to 8 weeks.

A second option with these patients is that you give them a 2-week prescription of an oral steroid. The advantage of that is that there is no issue with regards to inhalation. If your symptoms get dramatically better with the steroids, then it leaves you with a diagnostic dilemma, because the steroid will treat asthma but it may also potentially treat other nonasthma conditions such as eosinophilic bronchitis or even some forms of interstitial lung disease.

Our practice is that if there is a high index of suspicion, general practitioners are to treat with inhaled steroids. If that does not help, then as a second line we would advise practitioners to either do a reversibility assessment or a bronchial provocation test. Our choice in this matter is to do either a methacholine challenge using the 2-minute tidal breathing method or to do a histamine challenge, because these are direct challenge agents. We would not advise using mannitol challenge because this can often cause and provoke a lot of coughing. That is our practice that we would normally advise practitioners who are seeing patients with a cough.