Causes and Diagnosis When You Can't Stop Coughing

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If you've been coping with a constant cough you may be very frustrated, in addition to being worried about what your cough might mean. What are the possible causes of this symptom, what questions might your doctor ask, and how is this kind of cough treated?

Common Causes of Constant Coughing
Verywell / JR Bee

Symptoms of Constant Cough

There really isn't a clear definition of a constant cough, but if you've been living with one you probably don't need a definition. A constant cough is one that interferes with your day-to-day routine or keeps you from getting a proper night's rest. It may be hard to catch your breath. It may lead to vomiting. It may leave you feeling totally exhausted.

But whether it's needing to speak on the job, attending school, caring for your children, or trying to sleep, constant coughing can clearly get in the way and reduce your quality of life.

Acute or Chronic

Coughs are usually described as acute or chronic:

  • An acute cough usually lasts three weeks or less.
  • A subacute cough lasts between three and eight weeks.
  • A chronic cough is defined as a cough lasting longer than eight weeks.

Your cough may be dry (non-productive) or you may cough up phlegm (a productive cough). If you do have phlegm, it may be clear, yellow, green, or even blood-tinged.

Your cough may occur alone, or you may have noted other symptoms. Sometimes it can be difficult to determine if you have two symptoms, or if one is related to the other.

For example, if you are feeling short of breath it may be difficult to determine if you are simply finding it hard to catch a good breath between coughing jags, or if you are truly experiencing difficulty breathing unrelated to your cough.


Causes of a constant cough can range from those that are serious to those that are mostly a nuisance. While some causes are more common than others when you add up all of the possible uncommon causes of a constant cough they are actually quite common. It's also important to note that a cough may be due to a combination of reasons.

Common Causes
  • Postnasal drip

  • Viral infections

  • Bronchitis

  • Allergies

  • Bronchospasm

  • Asthma

  • Acid reflux

  • Smoking

  • Medication

  • Exposure to irritants

  • Croup

  • Pneumonia

  • COPD

  • Whooping cough

Less Common Causes
  • Lung cancer

  • Aspiration of a foreign body

  • Tuberculosis

  • Bronchiectasis

  • Blood clots in the lung

  • Congestive heart failure

  • Collapsed lung

  • Fungal infections

  • Other lung diseases

Common Causes

These are some of these more common causes of an unrelenting cough:

  • Postnasal drip: Perhaps the most common cause of a constant chronic cough is postnasal drip due to sinusitis or rhinosinusitis (inflammation of the nasal passages). This cough is often productive of clear to whitish phlegm and accompanied by throat clearing.
  • Viral infections: Infections such as the common cold and influenza are a common cause of a non-stop cough. The cough may be accompanied by other cold symptoms such as a runny nose, or symptoms of the flu, such as body aches.
  • Bronchitis: Both acute bronchitis and chronic bronchitis can cause someone to cough constantly. With chronic bronchitis, the cough is usually productive of phlegm.
  • Allergies: Environmental allergies such as a mold allergy, as well as food allergies, may cause a cough.
  • Bronchospasm: Constriction of the airways (bronchospasm) due to an allergic reaction or asthma can cause a cough. The cough is often accompanied by wheezing with expiration (breathing out). If there is also swelling in the neck or tongue or shortness of breath, this can be a medical emergency (anaphylactic shock).
  • Asthma: Asthma may be a cause of a steady cough. It is often accompanied by wheezing and chest tightness, but in some people, a cough is the only symptom, and may be referred to as "cough variant asthma."
  • Acid reflux: Gastroesophageal reflux disease (GERD) can result in constant coughing due to the back up of acid from the stomach. Episodes of coughing at night after lying down and hoarseness the following morning are common. GERD may have symptoms of heartburn or indigestion, or a cough may be the only symptom.
  • Smoking: A smoker's cough can be non-stop at times. It is usually worst in the morning and is often productive of phlegm. Smoking is also a common cause of other respiratory ailments such as chronic bronchitis and even lung cancer. If you smoke, ask yourself if your cough has changed in any way.
  • Medications: ACE inhibitors, medications that are used to treat high blood pressure and heart failure, may cause someone to cough night and day. Examples of ACE inhibitors include Vasotec (enalapril), Capoten (captopril), Prinivil or Zestril (lisinopril), Lotensin (benazepril), and Altace (ramipril).
  • Exposure to irritants: Exposure to secondhand smoke, wood smoke, cooking fumes, dust, and toxic chemicals can cause someone to cough repeatedly.
  • Croup: In children, croup can cause a ceaseless barking cough.
  • Pneumonia: Both viral and bacterial pneumonia can cause a cough, often accompanied by a fever.
  • Chronic obstructive pulmonary disease (COPD)COPD is an important cause of a continuous cough, often accompanied by shortness of breath.
  • Whooping cough: With whooping cough (pertussis) periods of unrelenting coughing are often broken up by a deep breath—the whoop of whooping cough. It's important to note that people may develop whooping cough even if they have had the diptheria/pertussis/tetanus vaccine (DPT).

Less Common but Important Causes

Less common causes of a constant cough include:

  • Lung cancer: Lung cancer is a less likely cause of a constant cough but is important to keep in mind. Lung cancer is most treatable in the early stages. Roughly 50%t of people with lung cancer have a cough at the time of diagnosis.
  • Aspiration of a foreign body: Choking on meat, pills, or other objects can cause a relentless cough, usually of sudden onset. An exception may be with small objects that lodge in smaller bronchi. The cough may be thought due to a viral infection but persists longer than usual. Sometimes a bronchoscopy is needed to reveal smaller foreign bodies.
  • Tuberculosis: While tuberculosis is fairly uncommon in the U.S., it does occur, especially among immigrants and people who have spent prolonged time abroad. In addition to a cough, weight loss and night sweats are among the other symptoms. Let your doctor know if you have traveled, for this reason, and other possible causes.
  • Bronchiectasis: Bronchiectasis, a condition in which recurrent infections and inflammation cause widening of the airways, can produce a continuous cough that is often worse with lying down.
  • Blood clots in the lung: Blood clots in the legs—deep venous thrombosis (DVT)—may break off and travel to the lungs (pulmonary emboli) resulting in an irritating cough and often shortness of breath. Symptoms of blood clots in the legs may include redness, tenderness, and swelling.
  • Congestive heart failure: Heart failure can cause an unrelenting cough. This cough may produce pink foamy phlegm and usually worsens with lying down. It is most often accompanied by shortness of breath.
  • Collapsed lung: A pneumothorax (collapsed lung) can cause a perpetual cough that often begins suddenly. In addition to a cough, people may note shortness of breath as well as "creptitus," a sensation of having bubble wrap under the skin of the chest and neck.
  • Fungal infections: Conditions such as coccidioidomycosis, histoplasmosis, and cryptococcosis, among others, may result in a constant cough.
  • Other lung diseases: Diseases such as sarcoidosis and other lung diseases often cause coughing.

When to Call Your Doctor

If your constant cough has lasted for more than a few days it is important to see your doctor—even if you think there is an obvious reason for your cough. Sometimes a constant cough can be a sign of something quite serious. Coughing up blood, even a small amount, should be evaluated by your doctor.

If you are experiencing shortness of breath, chest pain, symptoms of blood clots (such as redness, swelling, or tenderness in your legs), or if your symptoms are frightening to you, call your doctor (or 911) immediately.

It's also important to call 911 immediately if you have stridor (a high-pitched wheezy sound with breathing in), your cough has a sudden onset, or if you have swelling of your tongue, face, or throat, as these symptoms may signal a medical emergency.


When you see your doctor, the first thing she will do is a careful history and physical. Depending on your history and your exam, other tests may include:

  • Chest X-ray: A chest X-ray may be done to look for pneumonia as well as other possible causes of coughing. Note that a chest X-ray isn't sufficient to rule out lung cancer, and may miss small tumors.
  • Blood tests: A white blood cell count (WBC) may be done to look for signs of viral or bacterial infections.
  • Spirometry: Spirometry, a test in which you see how much air you can blow out of your lungs in one second, may be recommended if your doctor is concerned about conditions such as asthma or emphysema.
  • Computerized tomography (CT) scan: If your cough persists, or if your doctor is concerned that you may have a serious cause for your cough, she may order a chest CT scan to get a more detailed look at your lungs and the surrounding tissues.
  • Bronchoscopy: A bronchoscopy is a test in which a small tube with a light is inserted through your mouth and into your large airways. This may be done if your doctor is concerned about a foreign body in your airways (from choking) or if they are looking for an abnormality such as a tumor.
  • Laryngoscopy: A laryngoscopy is a procedure in which a tube that is inserted through the mouth to visualize the area around your vocal cords.
  • Esophageal pH testing: Acid reflux is a fairly common cause of coughing, and some people do not experience typical symptoms of heartburn. With esophageal pH testing, doctors can check for signs of acid reflux.

Questions Your Doctor May Ask

Be prepared to provide answers for these likely questions:

  • When did your cough begin?
  • Is your cough dry or wet (for example, are you coughing up phlegm?)
  • Have you vomited after coughing?
  • What time of day is your cough the worst?
  • Have you had a fever?
  • Have you been exposed to anyone who is ill?
  • How long have you had the cough?
  • Do you smoke, or have you ever smoked?
  • Are you exposed to secondhand smoke?
  • What other symptoms have you been experiencing? For example, have you coughed up blood, do you feel short of breath, have you experienced hoarseness or wheezing?
  • Do you experience heartburn?
  • Do you have any general symptoms such as unexplained weight loss or fatigue?
  • Do you have any allergies?
  • Are you exposed to mold or do you live in a home that has experienced water damage?
  • Have you had any episodes of choking?


The treatment of a constant cough will depend on the underlying cause. Natural cough remedies, such as a teaspoon of honey, humidity (such as a vaporizer), and rest may be helpful no matter the cause. Drinking enough fluids can thin secretions and is almost always helpful.

Lemon drops or other hard candies may be soothing, but never give these to children. Over-the-counter cough syrups should not be used for children unless recommended by a pediatrician.

If you think you have an infection, avoid using antibiotics that you may have on hand from the past. Using old antibiotics will not help if you have a viral infection, and may instead increase the chance of developing antibiotic resistance or delay the diagnosis of your cough.

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Article Sources
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Additional Reading
  • Burki, T. A Constant Chorus of Coughs. Lancet Respiratory Medicine. 2015. 3(6):434.

  • National Institutes of Health. Medline Plus. Cough. Updated 02/07/18.

  • Satia, I., Badri, H., Al-Sheklly, B., Smith, J., and A. Woodcock. Towards Understanding and Managing Chronic CoughClinical Medicine. 2016. 16(Suppl 6):s92-297.

  • Soni, R., Ebersole, B., and N. Jamal. Treatment of Chronic CoughOtolaryngology – Head and Neck Surgery. 2017. 156(1):103-108.