what helps a dry hacking asthma cough?
<answer> A positive methacholine challenge. <context> · Asthma. Chronic cough as the only sign of asthma is often referred to as cough variant asthma. It’s usually a dry, hacking cough that may worsen following exercise, talking, laughing or crying. Pulmonary function tests may be normal or reveal a mild obstructive pattern. When pulmonary function tests are normal, a positive methacholine challenge helps support the diagnosis of asthma.