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?
Definition of a Constant CoughThere 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, caring for your children, or trying to sleep, constant coughing can clearly get in the way.
Coughs are usually described as acute or chronic. An acute cough usually lasts 3 weeks or less, whereas a chronic cough is defined as a cough lasting longer than 8 weeks. (Between 3 and 8 weeks it's classified as subacute.) Your cough may be dry (non-productive) or you may cough up phlegm (a productive cough.)
Possible CausesCauses of a constant cough can range from those that are serious to those that are mostly a nuisance. Common, and less common but important causes may include:
Common Causes :
- 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 phegm 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.
- 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.
- Acid reflux - Gastroesophageal reflux disease (GERD) can result in constant coughing due to the back up of acid from the stomach. A very common cause of coughing, GERD often causes episodes of coughing at night after lying down, and often results in hoarseness the following morning.
- Smoking - A smoker's cough can be non-stop at times. It is usually worst in the morning, and is often productive of phlegm.
- Medications - ACE inhibitors, medications that are used to treat high blood pressure 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 bacteria pneumonia can cause a cough, often accompanied by a fever.
- COPD - Chronic obstructive pulmonary disease (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.
Less Common, But Important Causes 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.
- Aspiration of a foreign body - Choking on materials such as meat, pills, coins, grapes, or other objects can cause a relentless cough as your body tries to remove the foreign material. A cough related to aspiration usually has a sudden onset.
- Tuberculosis - While tuberculosis is fairly uncommon in the United States, it does occur, especially among immigrants and people who have spent prolonged periods of time abroad. In addition to a cough, people may also experience weight loss and night sweats among other symptoms.
- 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 including redness and swelling may also be present.
- Congestive heart failure - Heart failure can cause an unrelenting cough. This cough may produce pink foamy phlegm and usually worsens with lying down.
- Collapsed lung - A pneumothorax (collapsed lung) can cause a perpetual cough that often begins suddenly.
- Other lung diseases - Diseases such as sarcoidosis and other lung diseases often cause coughing.
DiagnosisWhen 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:
- A chest x-ray - A chest x-ray may be done to look for pneumonia as well as other possible causes of coughing.
- 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.
- A 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 she is 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
- 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?
TreatmentsThe treatment of a constant cough will depend upon the underlying cause. Home 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. 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. 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.
When to Call Your DoctorSometimes a constant cough can be a sign of something quite serious. 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. Coughing up blood, even a small amount, should be evaluated by your doctor.
If you have a constant cough that 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.
National Heart Lung and Blood Institute. How is Cough Treated. Updated 10/01/10. http://www.nhlbi.nih.gov/health/health-topics/topics/cough/treatment.html
National Institute of Health. Medline Plus. Cough. Updated 05/25/11. http://www.nlm.nih.gov/medlineplus/ency/article/003072.htm