Causes of Chronic Cough – Persistent, Constant Coughing

Definition of Chronic Cough

A cough is a forceful ‘push’ of exhaled air that is either done voluntarily or as a reflex action (involuntary). A chronic cough is usually considered to be any cough that is persisting for more than 3 months. It may be constant, where the patient coughs every few minutes or it can be episodic, where a patient goes into a bout of coughing and it then subsides. A chronic cough is usually persistent because the cause of the cough may be a chronic disorder or the patient is constantly exposed to the same factors that may trigger the cough.

Types of Cough

Broadly, a cough can be divided into :

  • Dry cough, non productive cough, in which no mucus is produced or coughed up.
  • Wet cough, or a productive cough, is when mucus is present, either heard in the lungs or airways (chest) or coughed up into the throat or mouth.

Causes of a Persistent Cough

Chronic Bronchitis

Chronic bronchitis is the most common cause of a persistent cough and is usually due to physical or mechanical causes rather than an infection. In contrast, acute bronchitis is often a result of an upper respiratory tract infection.

A cough associated with chronic bronchitis is commonly known as a ‘smoker’s cough‘ due to the prevalence of this condition in tobacco smokers. Smoking leads to chronic obstructive bronchitis, a type of chronic obstructive pulmonary disease (COPD), which results in a loss of elasticity of the lungs, swelling of the airways with mucus production and destruction of the air sacs in the lungs. Frequent clearing of the throat, shortness of breath (dyspnea) and difficulty in breathing, especially while asleep, are the most common symptoms that accompany the persistent wet cough in chronic bronchitis.

Post-Respiratory Tract Infection Cough

This cough usually persists for a few weeks to months after a respiratory tract infection or generalized infection that involves the respiratory tract, like the seasonal flu (influenza). It is more common after a viral respiratory tract infection and usually the cough is dry or non-productive.

Hay fever & Post-Nasal Drip

The primary cause of these conditions is an allergic reaction and the typical symptoms of an allergy may be present. Sneezing upon waking in the morning, red itchy eyes (especially after dusk), nasal congestion and sensitivity to environmental, physical and sometimes ingested (food) factors indicates the presence of an allergy affecting the upper respiratory tract. The cough in post nasal drip is usually dry and a result of mucus ‘tickling’ the back of the throat. In contrast, a cough is not common in hay fever where the mucus is expelled through the nose (‘runny nose’). If the mucus in post nasal drip enters the lower airways and settles in the lungs, the cough may be productive or wet.

Asthma

Asthmatics may cough in response to sudden exposure to certain trigger factors like exercise, inhaled (airborne) allergens, ingested (food and drink) allergens, environmental factors (typically severe cold), upon waking from sleep, and stress. If exposure to the trigger factor persists, wheezing may become evident when coughing, giving a  slightly high-pitched tone to the cough with shortness of breath.

Gastrointestinal Causes

A chronic cough may develop in gastroesohpageal reflux disease (GERD) and is prominent in the morning, after waking, due to the irritation of the pharynx (back of the throat) by gastric contents (partially digested food and acid) while asleep. A cough may also occur in GERD during or after an episode of reflux ‘heartburn’. Other gastrointestinal conditions that may cause aspiration (food or liquids entering the lung from the esophagus) may also cause a cough.

Infections

Long term infections like TB (tuberculosis) and fungal respiratory infections, like Pneumocystic carinii pneumonia, may cause a chronic cough. This is more common in immunocompromised patients, like HIV/AIDS, and may be accompanied by other symptoms like night sweats, coughing up blood (hemoptysis), fever, weight loss and generalized lymphadenopathy (enlarged lymph nodes throughout the body). Pertussis, or whooping cough, is another infectious cause of a chronic cough and is more commonly seen in children. Infectious causes of a chronic cough typically causes a wet cough.

Drugs

Certain medication, like ACE inhibitors, which is used in cardiovascular conditions, especially hypertension, is known to cause a chronic cough. This is usually a side effect of the drug and subsides upon discontinuing the medication.

Cardiac Failure

Cardiac failure may be a slow progressing condition that causes pleural effusion (‘water in the lungs’) and this results in shortness of breath (dyspnea), a dry cough with the sound of bubbling in the lungs when breathing (crepitations).

Tumors

This is a rare cause of a chronic cough and presents with many of the signs and symptoms evident in an infection.

Other Causes

Rare causes of a chronic cough include tonsil stones, chronic tonsillitis and an enlarged thyroid gland (goiter) where the constant sensation of an object in the throat (globus sensation) may result in a persistent cough. Cystic fibrosis and psychogenic causes are rare causes of chronic cough and may be more often seen in children.

Diagnostic Investigation of a Chronic Cough

A chest x-ray is the most common diagnostic tool used when investigating a chronic cough. Coupled with the patient’s medical history, signs and symptoms as well as clinical findings during the physical examination by a doctor, the cause of the chronic cough may be isolated. Additional investigations like allergy testing (asthma, post nasal drip), bronchoscopy and endoscopy (gastrointestinal causes) and sputum testing (TB, fungal infections, pertussis) may be necessary to diagnose the cause of a chronic cough.

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  • Dr. Greg

    Salishangel

    GERD and COPD are 2 different conditions. Before diagnosing either condition, please consult with you doctor. None of these conditions should hamper your social life and if you have confined yourself to your home due to either of these conditions, then it may be more of a psychological issue rather than a physical condition. In that case, psychotherapy may be required.

  • salishangel

    Hello,

    I would like to to know please, if COPD came before the GERD ? or visa -versa?

    I have been suffering for awhile now and it seems to be getting worse. My theory is it is getting worse due to the lack of physical movement, and the lack of going outside the house to do regular daily routine stuff .It’s a viscious circle, one gets sick with GERD & COPD , is possibly frieghtened like me with these symptoms , thus one is afraid to go anywhere in case they get sick like the last time, so you start to do less to avoid being sick, but then , atrophy sets in, and you illness worsens .. what is one to do ? I’m afraid I’m not going to get better.So this is just a thought the Universe hears, thus will it come true ? I’m confused !! help . thanks for reading .

  • Magdalene

    I have suffered with cough since 2003,itching of the throat triggers the coughing and sneezing. This coughing is on and off ie i can spend like 2months without it then it comes back.
    The doctors treated me but no cure.
    please advise.

  • Dr. Greg

    Hi Magdalene

    Sounds like a case of post nasal drip. Do you suffer with any other nasal symptoms which may have been previously diagnosed as hay fever or sinusitis? Morning sneeze, red itchy and watery eyes, especially in the evening or in certain seasons? Do you smoke?

    I would advise that you consult with an ENT specialist who will scope the area and provide a definitive diagnosis. It may even be chronic suppurative tonsillitis which causes a chronic itch at the back of the throat.

  • Magdalene

    They have never diagnosed me of any those, and am not a smoker. Except that I get this attack when there is dust, when am in a very stressing period or after getting flu. Dr checked me for TB was -ve HIV -ve. Now Dr what can I use to get cured.

  • Irshmn3

    My sister has suffered from a chronic cough that has progessively become worse. It is exacerbated by talking to the point that she cannot finish a conversation. She had was allergy tested and was negative for everything. She coughs so bad in the morning that she will eventually vomit– then she is better. Her physicians are baffled. She is 58.

  • Dr. Chris

    Hi Irshmn3

    There are a number of possible causes, as listed in the article above, which should be investigated. Is she a smoker? Does she suffer with a post nasal drop? Has her tonsils been examined for any chronic inflammation?

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  • http://www.google.com Ritu Mittal

    Actually I am suffering from caugh and gastric since last two months .Usually I have a problem early morning or when sometime I wake at midnight.I checked myself to 4 physician and they gave several antibiotics but that was not a temporary remedy.Please suggest me

  • Dr. Chris

    Hi Ritu Mittal

    I am unsure what you mean by gastric so for now I am going to assume it is reflux. Reflux can cause an irritation at the back of the throat (pharynx). This tends to occur after sleeping when the supine position (lying down flat) allows the acid to rise up and pool at the back of the throat. This causes inflammation of the throat. Patients typically complain of a sore throat that is worse in the morning upon waking. This inflammation often leads to persistent coughing throughout the day in a bid to clear the ‘irritation’ but it is not effective in doing so. Treat the acid reflux and the irritation will ease ultimately settling the cough to some degree.

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  • Kristen Marsh

    I am a long time chronic pain sufferer.I have been to 4 doctors in the last few years and they can not figure out what the cause is.In 2007 the pain affected my whole body to the point where I couldnt go out or walk for long periods of time.It would cause me to fall and then my lower half would become deadweight and feel like someone is sitting on my lower back just above the buttocks.After awhile the pain affected my back,hips and upper thighs.When that would happen the muscles in my thighs would feel like they were being stretched and would tighten up.What would cause this to happen? please help?

  • Dr. Chris

    Hi Kristen

    Please note that this article is discussing Chronic Cough. Please post your question on another related article.

  • christine

    I have acquired a chronic cough two years ago after a severe bronchis bout. Have had lung x-ray, but no allergy testing. Yesterday, on the way to a nail salon, it suddenly hit me that they could be causing this. Rather than getting my normal “fill”, I had them removed and hoping that the “little voice” was correct.

  • Desiree I.

    Hi. I’ve had a persistent cough for about a month and a half now. Have a history of asthma, but have been off my inhaler for about 3yrs. Earlier this summer I started feeling groggy and feeling under the weather [clogged ears, congestion && wet cough]. After my second visit to the hospital I was diagnosed with sinusitis and given an antibiotic and zyrtec. after that trial 2wks later my cough worsened. my chest hurts from coughing throughout the day && I need my inhaler to help my shortness of breath.

    Any suggestions?

  • Dr. Chris

    Hi Desiree

    It is not uncommon for a person with an allergic condition (asthma, hay fever/sinusitis, eczema) to move between these conditions throughout their lifetime. While your asthma may have settled, it is likely that your sinusitis/hay fever has flared up. This may be leading to post nasal drip where the mucus is dripping to the back of the throat and some of it is entering the airways.

    This will cause a “wet cough”, irritate the airway lining and may trigger bronchoconstriction which is why you are responding to the inhaler. You should see an allergist to have this condition monitored and managed appropriately. You may find that with time (months or years) the sinusitis will settle and you may be symptom free only to find that your asthma starts up again. This can go on for years or even your entire lifetime.

    If you are smoking or have had a recent upper respiratory tract infection, this could also account for your symptoms. But from what you say, it is most likely due to an allergic disposition. Speak to your ENT or pulmonologist about a referral to an allergist.

  • peter

    hi,
    i have this constant night cough.i dont have none of this symthoms in the day or morning,only at night. constant swallowing when lying down,tickling in the throat, bring up bits of indegisted food, leading to vomiting sometimes. sometimes hard swallowing food when eating. i used to smoke and stopped 3yrs ago. been the doctors and he keeps giving me cough syrup which does not help. any suggestions? thanks.

  • Dr. Chris

    Hi Peter

    This could be related to a post nasal drip. Many allergy sufferers report that their symptoms intensify in the evenings. The mucus dripping to the back of the throat will cause a tickling sensation and a shallow cough.

    If you have chronic tonsillitis, specks of food can get trapped in the crevices, and will come out when coughed up. Sometimes older food that has partially decomposed will look like white specks, similar to rice.

    Lastly, you also have to consider GERD (gastroesophageal reflux disease/acid reflux). You may be regurgitating some of your food and the gastric acid may be irritating the back of the throat which you are perceiving as a “tickling” sensation. This is more likely to get worse when you are lying down, especially if it is associated with a weak LES (lower esophageal sphincter) which prevents the stomach contents from rising up the esophagus (food pipe).

    You should speak to you doctor and he should refer you to an ENT at this point. Given your previous history of smoking, it should be investigated by a medical specialist.

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  • sheema majid

    hi sir,
    i need ur favour, my dad is a chronic smoker n he is suffering frm chronic persistant cough since yrs, the cough is productive

  • Dr. Chris

    Hi Sheema

    It is most likely chronic bronchitis which develops in smokers. Even if it resolves, it may return within a few months to a year. The only way to stop this is for him to quit smoking. Antibiotics may be necessary to prevent or quickly treat any secondary bacterial infection. Bottom line – there is no way to stop this without him giving up his smoking habit. It will gradually get worse.

  • Pete

    I have been suffering with a chronic cough for months. It is worse at bedtime. I have the “throat tickle” and non productive cough. Sometimes if I cough long and hard enough I will bring up mucous. My biggest problem though is when I am driving and I start coughing, I get so lightheaded that I nearly black out, which is very dangerous. This also happens when I am not driving. I am concerned that I might actually blackout and cause harm to myself or others.

  • Auraflash

    I have some sort of sickness but it seems to be getting better.. but im left with the sore cough. When i cough it hearts my stomach, my head (like a huge pulse) and when i breath i have a weezy chest.. My throat is ichy which causes me to couph.
    Taking cough syrup..and other medicine but isnt seeming like it’s getting any better, but worse. Any1 have a clue?

  • Dr. Chris

    Hi Pete

    You need to see a doctor and find the exact cause of this cough. It may be triggered from higher up the respiratory tract, possibly as a consequence of post nasal drip. This may aggravate when lying flat and will cause the “tickle” that you are describing. While coughing will usually not bring up any sputum, excessive coughing can push out a small amount of sputum which may be normal (mucus + saliva).

    Refer to the article on Sputum Color for information on the causes of different colors of sputum. This may help in guiding you to a possible cause.

    Another possibility here is acid reflux. The rising stomach acid triggers bouts of coughing as it causes intense irritation and stimulation of the cough reflex. Of course there are a number of diseases of the lung and airways that could be causing these symptoms. if you are a long term smoker, this may be a sign of chronic obstructive pulmonary disease (COPD).

    Any cause of severe, constant coughing can affect ventilation (gas transfer in the lungs) and even heart activity. This may account for the dizziness. The latter, a disruption of your heart rhythm, is more likely to occur in a person with a cardiac condition. You should have this investigated – given the prominence of your throat symptom prior to the onset of the coughing, I would advise that you consult with an ENT (ear-nose-throat specialist / otolaryngologist).

  • Dr. Chris

    Hi Auraflash

    It could be bronchitis. Even though it may be getting better, you should see a doctor. Cough syrup offers only limited relief. You may need antibiotics and so on if it is a bacterial infection.