Cough is a symptom that everyone has experienced. Whether it be an aspiration episode or catching the common cold, we have all coughed at some point. Most of the time, the cough resolves itself within a matter of days. However, many patients experience chronic cough, defined as a cough that continues for over eight weeks.
Chronic cough is a common condition seen in pulmonary clinics and can be frustrating for both patients and physicians. Patients continue having symptoms despite trials of different medications. Physicians find it difficult to make a specific diagnosis and improve symptoms. This article sheds light on my approach to chronic cough and general recommendations for patients.
Importantly, patients should be aware of the alarm or red flag signs associated with a cough. These signs include (but are not limited to) smoking history, coughing up blood or purulent-appearing (pus-like) phlegm, chest pain, shortness of breath, voice changes, difficulty swallowing or eating, vomiting, recurrent pneumonias, body swelling, fevers or chills, and weight loss. If any of these symptoms are present, a serious medical condition such as pneumonia, lung cancer, or heart failure could be present. Prompt diagnosis and treatment is necessary when red flag signs are present. Make sure to contact your physician or seek emergency care as soon as possible if this is the case!
Fortunately, the majority of patients with chronic cough have no red flag signs. Causes of chronic cough in the absence of red flag signs include post-nasal drip, asthma, gastroesophageal reflux, non-asthmatic eosinophilic bronchitis, and medication side effects. Details including runny nose, sinus congestion, allergies, new exposures in the home or workplace, travel history, timing during the day, presence and color of sputum, relationship with food, history of asthma, wheezing, and current medications help differentiate the common causes. Treatment options include intranasal sprays and washes and antihistamines for post-nasal drip, inhalers for asthma and non-asthmatic eosinophilic bronchitis, anti-acid medications for gastroesophageal reflux, and over-the-counter cough suppressant including cough drops. Because of the risk for silent aspiration, I ask all patients with chronic cough to eat smaller meals and go to sleep no earlier than three hours after completing dinner. Consider asking your physicians about stopping medications such as ACE-inhibitors that may be causing cough. Obviously, patients should quit smoking and vaping.
A small subset of patients will continue coughing despite extensive treatment regimens. This is a discouraging situation, especially in light of the COVID-19 pandemic. In these cases, my preference is to start from square one. My patients and I reassess their medical and cough history, rule out red flag signs, and review medications and inhalers to make sure they are taken correctly. Sometimes our initial diagnosis is incorrect and a different treatment regimen should be recommended. More testing is usually necessary. Chest x-ray, CT scans, sinus imaging, pulmonary function testing, esophageal studies, cardiac workup, allergy testing, and bronchoscopy are some of the studies to consider.
If a cough still persists after extensive testing and treatment regimens, cough hypersensitivity syndrome can be presumed to be the diagnosis of exclusion. Cough hypersensitivity syndrome is a neuropathic process where patients are especially sensitive to triggers of cough. The good news is that without red flag signs, this is a benign process without long-term consequences. The bad news is that patients will continue having the bothersome cough. Certain medications, including anti-seizure and antidepressant medications, can be tried but the side effects can be significant. Referrals to speech therapy programs can be helpful but usually do not completely resolve the cough. A new medication is completing phase three trial and hopefully will offer a permanent solution.
Despite being a seemingly simple problem to solve, management of chronic cough continues to humble all pulmonologists. At the end of the day, we can only offer reassurance about the absence of cancer and lung disease for some patients with chronic cough.
Kelly Fan, MD
Dr. Fan is a pulmonologist and critical care attending physician with clinical expertise in advanced asthma, bronchiectasis, bronchoscopy, COPD, interstitial lung disease, lung cancer, lung infections, pleural disease, and pulmonary vascular disease. Dr. Fan is a Doctorpedia Founding Medical Partner and the Chief Medical Officer of Doctorpedia's Lung Health channel.