The Relationship Between Chronic Cough and Laryngopharyngeal Reflux

Chronic cough is multifactorial in origin, may affect quality of life adversely, and often poses a diagnostic challenge for physicians. Laryngopharyngeal reflux (LPR) is one common contributing factor for chronic cough, but the mechanism by which reflux causes cough remains unclear. Research investigating the relationship between chronic cough and LPR has focused largely on reflux from the perspective of gastroenterology, rather than otolaryngology.

The purpose of our study was to investigate the relationship between chronic cough and LPR by using the objective results of 24-hour pH impedance studies.

We conducted a retrospective chart review of all patients who presented to the voice center of the senior author (RTS) with a chief complaint of chronic cough and no previous diagnosis of reflux. Patient demographics, past medical history, laboratory data, and exam findings during the initial visit from 2015 to 2020 and at follow-up were analyzed.

We identified 28 patients who presented with a chief complaint of chronic cough and who had not been diagnosed with or treated for reflux previously. Twenty-three had additional risk factors for chronic cough (asthma, chronic sinusitis, and bronchial schwannoma). All 28 had findings consistent with LPR upon exam. Treatment with reflux medications and lifestyle modification decreased the reflux finding score significantly from 11.39 to 9.21 (P= 0.005). Of all, 60.7% of patients reported subjective improvement in cough symptoms. The cough had improved in 50.0% and had resolved completely in 10.7%. Patients with VF paresis were less likely to report improvement in their cough. Further workup was performed for the 11 patients who had cough that did not resolve completely after reflux treatment. Detectable levels of antimycoplasma antibodies were found in nine patients, and antipertussis antibodies were found in two patients. Six patients followed up after a course of clarithromycin, three of whom had experienced improvement in their cough.

Our findings suggest that LPR may be a prevalent contributing or etiologic factor for chronic cough. The expected improvement after initiating reflux treatment is 60% at 3 months. Cough resolved completely in 10% of patients at 4 months. Nonresponders may have other contributing causes of cough, including esophageal dysmotility, mycoplasma, pertussis, and other contributors. Further studies are needed to confirm or refute these findings.