A continuing cough that has been present for more than eight weeks in adults and more than four weeks in children is often considered to be a chronic cough. A chest x-ray may be normal even though the cough persists. Many causes of chronic cough are related to problems in the lower airway, such as lung infections. Some of these, such as lung infections, can be identified by an abnormal chest x-ray. However, other common lung causes including asthma and chronic bronchitis may present with a normal chest x-ray.
If you have a chronic cough that has not been explained or diagnosed, you should seek medical care through your primary care physician. It is important to remember that there are many causes of cough not directly related to the lungs and depending on their evaluation, they may refer you to a specialist such as an ENT (ear, nose, and throat) specialist, or otolaryngologist, for further evaluation.
Typically, the search for the cause of your chronic cough can involve several different systems in the body. A thorough history and physical examination will help decide which direction your physician will take as well as any diagnostic studies or consultations that may be necessary. Once lung infection such as pneumonia or tumors have been ruled out through x-ray examination, there are several other common causes that should be considered. These include:
Chronic bronchitis related to smoking—Chronic airway inflammation related to smoking is very common. If you smoke, quitting is the best thing you can do for your health. Smoking weakens your immune system and increases your risk of lung, throat, and other cancers.
Blood pressure medication—Some commonly prescribed blood pressure medications known as angiotensin-converting enzyme (ACE) inhibitors can cause a dry cough. Common medications in this category include enalapril (Vasotect®) and lisinopril (Prinivil®, Zestril®). If you have a dry, chronic cough and no other causes are found and you are taking one of these medications, speak to your primary care physician about finding an alternative blood pressure medicine.
Upper airway cough syndrome—Many nasal disorders cause rhinitis resulting in nasal drainage, which can cause cough and lead to a disorder called upper airway cough syndrome (UACS). These disorders can cause a persistent feeling of drainage in your throat, called post-nasal drip, which can cause frequent coughing and throat clearing. An evaluation for these disorders may include testing for allergies (such as to tree pollens or animals) and possible evaluation by an ENT specialist for chronic rhinosinusitis or other disorders.
Over-the-counter treatments for UACS may include nasal saline rinses (e.g., neti pot), steroid nasal sprays (e.g., Flonase®), or oral antihistamines and allergy medications (e.g., Allegra®, Zyertec®, or Claritin®). Prescription treatments and procedures for UACS can include nasal antihistamine sprays (e.g., Azelastine®) and allergy immunotherapy treatment. There are effective surgical procedures available for certain conditions that have failed medical management.
Asthma—Asthma refers to inflammation of the lower airways causing constriction and spasm that is often associated with allergy issues and aspirin sensitivity. Often there is a family history of asthma or allergies to the environment. You can speak to your primary care physician or pulmonologist about evaluation and treatment for asthma. Some ENT specialists also diagnose and treat asthma.
Gastroesophageal reflux disease and laryngopharyngeal reflux—When acid repeatedly “refluxes” from the stomach into the esophagus alone, it is known as gastroesophageal reflux disease (GERD). If contents in the stomach come up into the throat, this is called laryngopharyngeal reflux (LPR). One of the main symptoms of reflux is chronic cough, and LPR may also contribute to post-nasal drip.
Neurogenic or neuropathic cough is a type of chronic cough related to overly sensitive nerves in the upper respiratory system and voice box, or larynx. It may affect as many as 11 percent of Americans. People are often diagnosed with neurogenic cough when they have not responded to other treatments for cough or other possibilities of a chronic cough have been excluded. Coughing episodes may be triggered by laughing, talking, moving, or inhaling cold air. It is more common in females and those in middle age or older.
Neurogenic cough may occur when the nerves that control sensation in your throat become sensitive to normal sensory stimulation such as breathing and swallowing, causing an abnormal reaction or cough. It can happen on its own, but it can also follow a recent cold or upper respiratory illness. Neurogenic cough may also come with a feeling that something is caught in your throat and excessive throat clearing, pain, tingling, burning, or constriction.
There are several treatments for neurogenic cough. Depending on individual situations, you may be advised to work with a speech language pathologist who can teach you cough retraining therapy before trying medications. They can show you strategies for suppressing and controlling your cough. You may be advised to try swallowing instead of coughing, sipping water, properly hydrating, and avoiding habits such as smoking, mouth breathing, caffeine, alcohol, and straining while speaking.
Your doctor will talk to you about the most appropriate medication for your condition. Gabapentin (Neurontin®) and pregabalin (Lyrica®) are common medications for treating neurogenic cough. Side effects may include dizziness, drowsiness, fatigue, headache, confusion, stomach upset, and weight gain. Amitriptyline (Elavil®) is a tricyclic antidepressant that has also shown to be effective in reducing cough-related symptoms.
In addition to therapy and medication, there are several in-office procedures that may be used to treat neurogenic cough. For example, materials such as steroids, numbing agents, filler, or botulinum (Botox®) may be injected into your throat or vocal cords to help reduce coughing. Speak with your ENT specialist about whether one of these procedures may be prescribed for you.