Evaluating a chronic cough: History often solves the mystery

April 1, 2006

A child's long-lasting cough is vexing for parents. One route to finding the cause is to, first, rule out serial viral illness and, then, piece together characteristics of the cough with findings from the history.

DR. SHERMAN is a pediatric pulmonologist in Roanoke, Va. The author has nothing to disclose in regard to affiliations with, or financial interests in, any organization that may have an interest in any part of this article.

What makes a child cough?

Once the afferent impulse is triggered by a chemical or mechanical receptor, the impulse travels to a cough center in the brain, eliciting the efferent limb of the cough reflex. Note that the utility of centrally-acting opioids, the most effective cough suppressant medications, is limited by adverse effects of drowsiness, nausea, constipation, and physical dependence. Research into receptor antagonists that act peripherally to decrease the afferent limb of the cough reflex is underway.7

The table lists the major causes of chronic cough among infants, preschool-age children, and school-age children and adolescents.

Nailing down the cause (the clues are in the cough!)

A child whose parent complains that he has been coughing for months may be experiencing a series of coughs that correspond to a series of viral infections-cough is common in viral infections, and children often have multiple contacts. Thus established, such a series cough following viral illnesses does not meet the criterion of chronicity-a cough that lasts longer than four weeks. This distinction between chronic cough and a series of coughs associated with a series of viral illness is important, and should be considered before you proceed further with the diagnostic evaluation.