Chronic Cough: Our Approach to Diagnosis and Treatment

By Rachel Taliercio, DO

Chronic cough, defined as cough lasting eight or more weeks, is a common therapeutic challenge. It is typically very troublesome to patients, and ineffective management is frustrating for both patients and clinicians. Many patients with chronic cough have been dealing with the condition for years; not uncommonly patients will report decades of cough. We have developed a systematic, multidisciplinary approach to the diagnosis and management of chronic cough. Pretesting includes chest radiograph, spirometry and exhaled nitric oxide. All patients undergo detailed laryngoscopy as part of the initial visit. Our multidisciplinary approach also includes consultation with pulmonology, ENT and speech therapy.

Diagnosis: common causes and response to therapy

Chronic cough is most commonly caused by one of the following conditions:

• Upper airway cough syndrome (UACS; postnasal drip due to allergic rhinitis, nonallergic rhinitis, irritant-inducted rhinitis, vasomotor rhinitis, or sinusitis)
• Asthma (“cough variant asthma”)
• Gastroesophageal reflux disease (GERD)

Patients often have more than one cause of cough, and empiric treatment should first be aimed at the most likely cause. Other less common causes of chronic cough include nonasthmatic eosinophilic bronchitis and laryngopharyngeal reflux.

Elevated levels of exhaled nitric oxide can correlate with eosinophilic airway inflammation. Spirometry measurement of airway hyperresponsiveness and history of clinical response to inhaled or systemic steroids can suggest cough-variant asthma. Clinical history, barium esophagram and esophageal pH monitoring can support a diagnosis of chronic cough secondary to GERD.

Response to empiric therapy, as defined by > 50 percent reduction in cough, will typically be reported within a few weeks of treatment for UACS or asthma. Clinical response to antireflux therapy can take several months. While an algorithmic approach aimed at empiric treatment of most likely causes is often successful, up to 40 percent of patients may not respond to therapy. It is important to assess for a more serious underlying reason for chronic cough (malignancy, interstitial lung disease, chronic infection or bronchiectasis), and CT chest may be indicated.

Refractory unexplained chronic cough: cough hypersensitivity syndrome is a diagnosis of exclusion

Consider cough hypersensitivity syndrome, also known as sensory neuropathic cough, in patients with a negative diagnostic workup with failed cough resolution following empiric treatment for more common causes of chronic cough. While the underlying mechanism is unclear, treatment with neuromodulator therapy has been shown to be effective. Medications include gabapentin and tricyclic antidepressants (amitriptyline and nortriptyline). Gabapentin has been shown to improve cough-specific quality of life in patients with refractory chronic cough, suggesting that central reflex sensitization is involved in this syndrome. Educating patients about possible side effects and having a protocol to guide titration of therapy is essential. Equally important is early referral to a speech pathology specialist. This therapy is an effective nonpharmacologic modality for the management of chronic cough.

Treatment at Cleveland Clinic

In 2016, otolaryngologist Paul C. Bryson, MD, and I launched the Chronic Cough Clinic to diagnose and treat patients with this often perplexing condition. Patients can receive comprehensive pulmonary function testing and upper airway evaluation, including the sinuses and the larynx, and gastrointestinal testing, including acid reflux testing, behavioral cough suppression with speech therapy, and allergy testing. Selected patients can receive behavioral cough suppression therapy and laryngeal Botox injections.

With experts from the Respiratory Institute, Head & Neck Institute and Digestive Disease & Surgery Institute working together, our hope is that patients in the Chronic Cough Clinic will see improvements in morbidity and quality of life.

Dr. Taliercio codirects the Chronic Cough Clinic and is staff in the Respiratory Institute.