CHRONIC COUGH Chronic cough has multiple causes. Where the general medical problem of pneumonia or chronic bronchitis has been ruled out by your primary care physician, a full allergy investigation may be of benefit. In addition to an evaluation for possible asthma, sinus disease, and allergies, other tests may be indicated. Our office has the latest state of the art Respiratory pH probe equipment as well as Methacholine challenge testing; both often needed to make a definitive diagnosis of your chronic cough.