Cough variant asthma: a review of the clinical literature.

Cough variant asthma is an occult form of asthma of which the only sign or symptom is chronic cough. This review examines 15 clinically oriented research articles on cough variant asthma and summarizes what is known about its frequency of occurrence, clinical presentation, diagnosis, treatment, and natural history. Cough variant asthma is a common problem among all ages that frequently goes unrecognized. Pulmonary function, as measured by spirometry, is often within normal limits. Any patient with a nonproductive, nocturnal cough lasting more than two weeks, should receive an empiric trial of bronchodilators. The natural history of cough variant asthma is variable. A significant proportion of patients followed over time develop the classic signs and symptoms of asthma, whereas for many patients, cough resolves without need for further treatment.