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What is the focus of this web site?

The most common cause of chronic cough in adults: inflammation of the upper airway, i.e., the nasal passages and the sinuses. The medical terms for this inflammation are 'rhinitis' (inflammation of the nasal passages), 'sinusitis' (inflammation of the sinuses, which are cavities of air in the head), and 'rhinosinusitis' (inflammation of both areas). This inflammation leads to production of mucus, which drips down into the pharynx (throat), larynx (voice box), windpipe (trachea), and lungs; these areas are filled with sensitive nerves that generate cough. Thus post nasal drip -- PND -- is the most common reason for chronic cough.


The major causes of rhinitis/sinusitis are viral infection, bacterial infection, allergy, and blockage [from various causes] of natural openings between the nose and sinuses. As a pulmonary specialist, I see many patients referred for chronic cough, and the vast majority have rhinitis/sinusitis with post nasal drip as the cause. Most referred patients with chronic cough do not have asthma or any lung disease as a cause.

Unfortunately there is much confusion and disagreement among physicians about diagnosis and treatment of upper airway inflammation. Confusion is mainly about diagnosis, disagreement mainly about treatment. This web site is devoted to clarifying these issues as much as possible, and to helping patients with chronic cough get proper treatment. (For list lovers, see 10 Common Myths, Misconceptions, Errors and Mistakes about Chronic Cough.)

This web site is written for the lay reader, but will also be of interest to health care providers who see patients with chronic cough: physician assistants, nurse clinicians, physicians. To further help medical professionals I have referenced many statements to the medical literature, and also provided a core reading list in the References. (These connected web sites are a work in progress, and will not be complete until this sentence no longer appears.)

What are the 'upper airway' and 'lower airway'?

The respiratory system extends from the mouth and nose down to the tiny sacs in the lungs (called alveoli) where oxygen is transferred into the blood stream. The respiratory system is one continuous tract, designed to bring in air from the atmosphere and deliver fresh oxygen to the blood. It traverses the head, neck and chest. (For a detailed discussion of the Respiratory System see Section A, in Breathe Easy: A Guide to Lung and Respiratory Diseases for Patients and Their Families.)

To illustrate the division of the respiratory system, put a finger at the top of your breast bone, at the base of your neck; you can feel a 'notch' at this point (called the surprasternal notch). Above the notch is the upper airway system, encompassing the nose, mouth, sinuses, back of the throat, larynx (voice box), and trachea. Below the notch (and inside your chest) is the lower airway system, which includes both lungs and all their branching airways; these airways are called bronchi and bronchioles, and they lead to the alveoli where fresh oxygen actually enters the bloodstream.

The respiratory system consists of upper and lower divisions. Air passages in the neck and head are the 'upper airway system' and include the nose, mouth, sinuses, back of the throat (including epiglottis), larynx (voice box), and trachea. Passages below the neck - the lungs and its branching airways - comprise the 'lower airway system'. Schematic from the AMA web site.

The following web sites show both a drawing of the sinuses and a sinus CT scan:
Drawing of the sinuses and a normal sinus CT scan
Detailed drawings of sinuses, plus normal and abnormal sinus CT scans

What is the confusion in regards to cough?

In regards to cough, the main source of confusion is the common assumption among both patients any many health care providers that the cause 'must come from the lungs.' This assumption on the part of many physicians, which often leads to erroneous diagnosis, can be traced to inadequate teaching in medical school and post-graduate training programs. (Click here for further discussion; skip it if medical education doesn't interest you.)

How does upper airway inflammation cause cough?

Since the respiratory tract is one system, any disease or condition affecting the topmost part (i.e., the nose and sinuses) can affect any lower part by GRAVITY. Remember, the system is open and continuous from the nose and sinuses down to the smallest division of the lungs (the alveoli). GRAVITY, plus the common tendency of mucus to form in the nose and sinuses, is why the most common cause of chronic cough is rhinitis and sinusitis.

While the most common source of mucus is in the nose and sinuses, the major cough centers are in other parts of the respiratory system; they are in the back of the throat (pharynx), the voice box (larynx), the wind pipe (trachea), and large airways of the lungs (bronchi). When mucus drips down from the nose and sinuses and touches these cough centers, nerves are stimulated that cause cough. (Mucus can also form in the lungs, which is the case in patients with asthma and chronic bronchitis. When that happens nerves in the bronchi are stimulated, resulting in cough.)

Mucus dripping from the nose or sinuses is called post nasal drip (PND). PND is the most common cause of chronic cough. If mucus stayed in the nasal passages and sinuses -- if it did not drip into the back of the throat and down toward the lungs -- then rhinitis and sinusitis would be an uncommon cause of cough.

What are the main conditions of the upper airway that cause cough?

The main conditions are 'rhinitis' and 'sinusitis'. In fact, many (if not most) patients who have one also have the other, i.e., rhinosinusitis, but for now it will be useful to categorize them separately.

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Inflammation of the nasal passages
acute: < 3 weeks
chronic: >=3 weeks
Inflammation of the sinuses (air cavities in the head)
acute: < 3 weeks
chronic: >=3 weeks


'Cold symptoms': stuffy nose, nasal discharge, feeling of mucus in back of throat (post nasal drip), cough
Same as rhinitis, plus: facial pain, fever, more severe or intractable cough. Most patients with sinusitis will have nasal inflammation as well (i.e., rhinosinusitis). Note: the only symptom of many patients with chronic sinusitis may be chronic cough.


Viral infection, allergy, rarely bacterial infection
Viral infection, bacterial infection, fungal infection, allergy, blockage by polyps. Sinusitis becomes 'chronic' when there is inadequate treatment and/or inadequate drainage of sinuses


Extremely variable: OTC decongestants, nasal sprays, prescription decongestants commonly prescribed. The longer symptoms continue, the more likely antibiotics will be prescribed. (Click here for list of commonly-used drugs for rhinitis/sinusitis)
Antibiotics are mainstay of treatment of bacterial sinusitis; however, because it is difficult to differentiate viral from bacterial sinusitis, virtually all patients with "sinusitis" or "rhinosinusitis" are treated with antibiotics. Also used are same drugs and remedies given for rhinitis. In addition, oral steroids (prednisone, methylprednisolone) are often used for chronic sinusitis, to decrease the inflammation. (Click here for list of commonly-used drugs for rhinitis/sinusitis)


Viral infection is a major cause of asthma, so viral rhinitis may be a prelude to asthma attacks in susceptible patients (mainly people who already have a history of asthma). Asthma can also develop following viral rhinitis. Finally, some patients suffering primarily from asthma also have concomitant rhinosinusitis.
Viral infection is major cause of asthma, so viral sinusitis may be a prelude to asthma attacks in susceptible patients (mainly people who already have a history of asthma). Asthma can also develop following sinusitis. Finally, some patients suffering from asthma also have concomitant rhinosinusitis.



(with links to
See books on Sinusitis ------>

How common are these conditions?

Very common. Statistics can be viewed from a disease perspective and also from a symptom perspective.

Disease perspective

  • Virtually every adult gets 1-3 "colds" a year (children get more). In 1996, the primary diagnosis of rhinosinusitis led to expenditure of.39 billion in the U.S. (Ray NF, Baraniuk JN, Thamer M, et. al. Healthcare expenditures for sinuitis in 1996; contributions of asthma, rhinitis, and other airway disorders. J Allergy Clin Immunol 1999;103:408-414.)
  • Chronic sinusitis affects an estimated 37 million Americans a year, and is the most common chronic condition for which people seek medical attention. Click here for more statistics on chronic sinusitis
  • People suffering from sinusitis miss on average 4 days of work per year due to their condition.
  • Approximately 0.5 to 2% of colds and influenza-like illnesses are complicated by acute bacterial sinusitis in adults (Berg O, Carenfelt C, Rystedt G, et. al. Occurrence of asymptomatic sinusitis in common cold and other acute ENT infections. Rhinology 1986;24: 223-225.)
  • The annual incidence of acute community-acquired bacterial sinusitis (a subset of all sinusitis) is alone about 20 million cases in the United States.
  • 200,000 endoscopic sinus operations (for chronic sinusitis) are performed yearly in the U.S.

Symptom perspective

  • Chronic cough, defined as a cough persisting for three weeks or longer, accounts for 30 million physician visits annually Irwin RS, et. al. Managing cough as a defense mechanism and as a symptom. A consensus panel report of the American College of Chest Physicians. Chest 1998; 114:133S-181S
  • Cough is the fifth most common symptom for which outpatient care is sought. Persistent cough can account for up to 38 percent of an outpatient pulmonary medicine practice (Irwin, RS, Curley, FJ, French, CL. Chronic cough. The spectrum and frequency of causes, key components of the diagnostic evaluation, and outcome of specific therapy. Am Rev Respir Dis 1990; 141:640.)
  • The cost of treating acute cough in the U.S. exceeds billion annually, not including the cost of diagnostic tests and medications Irwin RS, et. al. Managing cough as a defense mechanism and as a symptom. A consensus panel report of the American College of Chest Physicians. Chest 1998; 114:133S-181S

Aren't there other causes of cough besides upper airway inflammation?

Yes, definitely. First, virtually any lung disease can cause cough, including asthma, a common cause of chronic cough. All lung infections can cause cough (pneumonia, influenza, tuberculosis, acute bronchitis). Cigarette smokers often have chronic cough, called 'smoker's cough' (actually chronic bronchitis). Other conditions not associated with the lungs can cause cough, including acid reflux from the stomach, and certain medications (particularly blood pressure medications called "ACE inhibitors"). While there are in fact numerous causes of cough (and a physician will consider them to arrive at proper diagnosis), by far the most common is upper airway inflammation, or rhinosinusitis. For further discussion of chronic cough, see:
Mayo Clinic on chronic cough
Medicinenet on chronic cough

So what's the most common cause of chronic cough?

When all studies on adults are analyzed the most common cause is post nasal drip (PND), mucus dripping from the nose and/or sinuses into the back of the throat, and then down into the larynx, trachea and lungs. PND FROM RHINITIS &/OR SINUSITIS IS THE MOST COMMON CAUSE OF CHRONIC COUGH IN ADULTS. It is not asthma or acid reflux, or pneumonia, or cancer, or drug reaction. (Also, chronic cough is virtually never a psychological problem; there is always a physical cause.)

Various studies show anywhere from 38% to 87% of cases of chronic cough are from post nasal drip (either the sole cause of a major contributor; see following references):

  • Irwin RS, et. al. Managing cough as a defense mechanism and as a symptom. A consensus panel report of the American College of Chest Physicians. Chest 1998; 114:133S-181S
  • Irwin RS, et. al. Chronic cough. The spectrum and frequency of causes, key components of the diagnostic evaluation, and outcome of specific therapy. Am Rev Respir Dis 1990; 141:640
  • Irwin RS, et. al. The Diagnosis and Treatment of Cough. N Engl J Med 2000; 343:1715.
  • McGarvey LPA, et. al. Evaluation and outcome of patients with chronic non-productive cough using a comprehensive diagnostic protocol. Thorax 1998; 53:738.

In my experience, the higher number for PND (87%) is closer to what we see in actual practice. The number two cause in various studies is asthma (ranging from 14% to 43%), followed by gastroesophageal reflux (10% to 40%), and chronic bronchitis (0 to 12%). The higher numbers add up to more than 100% since multiple causes of cough were found in many patients.

In these and other studies, more than one cause of chronic cough was found in 18% to 72% of patients. Given that multiple causes are often present, treatment for one condition (e.g., post-nasal drip) may improve cough but not cure it until another cause is found and treated (e.g., acid reflux).

What about in children?

According to Dr. Irwin, the most common cause of chronic cough in children is asthma, followed by PND and then GERD. (See Irwin RS. Silencing Chronic Cough. Hospital Practice, January 1999.)

Is GERD (gastro-esophageal reflux disease) a common cause of chronic cough?

No. In fact, GERD is probably the most over-diagnosed cause of chronic cough. (Note: In Great Britain and other countries the condition is known as GORD, because it is spelled gastro-oesophageal reflux disease.) GERD is a 'fashionable' diagnosis, often rendered by doctors after just a throat exam, or sometimes not even that. In fact GERD is uncommon (as a cause of chronic cough) and difficult to diagnose. To be certain of the diagnosis the patient has to undergo an uncomfortable stomach acid study, where a tube is inserted into the stomach to measure acidity. More commonly, the diagnosis is assumed and the patient is treated empirically with a drug to combat the acid. The best drugs for GERD are called 'proton pump inhibitors', which include:

They are all effective, and the one prescribed seems to depend as much on formulary considerations (i.e., cost to the health care provider) as on physician preference.

What is the most common cause of chronic cough in other countries?

Same as in the U.S. Several foreign studies present results that are typical of what we see in a non-academic outpatient practice. One study, from Italy (Causes of chronic persistent cough in adult patients: the results of a systematic management protocol. Marchesani F, et. al. Monaldi Arch Chest Dis 1998 Oct;53(5):510-4) found the following causes of chronic cough (mean duration of cough 32.7 months!) in 87 patients:

- sinusitis or chronic rhinitis plus post-nasal drip in 56% of patients
- chronic bronchitis in 18%
- asthma in 14%
- gastro-esophageal reflux (GERD) in 5%
- post nasal drip and GERD in 6%
- asthma and GERD in 1%

By applying specific therapy the authors were able to successfuly cure the cough in 79/87 patients (91%).

Another study, from Saudi Arabia found the following diagnoses (either sole or contributory cause) in 100 outpatients with chronic cough:

- rhinosinusitis in 60%
- asthma in 26%
- gastro-esophageal reflux in 9%
- postinfectious cough in 8%
- bronchiectasis in 5%

(Chronic cough at a non-teaching hospital: Are extrapulmonary causes overlooked?, by Al-Mobeireek AF, et. al. Respirology 2002 Jun;7(2):141-146)

The authors concluded: "...chronic persistent cough is a common benign disorder that rarely requires specialized investigations and is easily treated once the causes are identified. The multiplicity of causes and extrapulmonary triggers of chronic persistent cough, particularly rhinosinusitis, are often overlooked. The principal causes in our series remain the same as in studies elsewhere, namely rhinosinusitis, asthma and GERD."

These two foreign studies are in line with experience in the U.S. The majority of patients with chronic cough have rhinosinusitis.

What is the most common cause of rhinosinusitis?

By far the most common cause is the same as that for the common cold: viral infection. Most viral infections, especially the common cold, are not treated with antibiotics. However, bacterial infections are treated with antibiotics. If the symptoms are confined to the nasal passages, and are typical of a common cold, and go away or abate in a few days, the patient should not be treated with antibiotics. However, if the symptoms suggest the sinuses are involved (e.g., facial pain, fever, expectoration of phlegm that looks like pus), then the patient may have a bacterial infection, and will likely need antibiotics. In truth, doctors can't distinguish between viral and bacterial causes of sinusitis. For this reason virtually all patients diagnosed with 'sinusitis' (acute or chronic) receive an antibiotic.

Why is treatment of rhinosinsitis so variable?

Variation in treatment is due to several factors:
  • There is no practical way to reliably distinguish between 'viral' and 'bacterial' infection of the upper airway, so the 'diagnosis' of a given patient's problem may vary among physicians.
  • Even accepting a specific diagnosis, there are no treatment guidelines universally accepted by the medical community.
  • There are a plethora of drugs available to treat rhinosinusitis; within each category of therapy (decongestants, nasal sprays, expectorants, and antibiotics) are numerous brands and dosage schedules. (Click here for list of commonly-used drugs for rhinitis/sinusitis)
  • Many patients get better without treatment, including most patients with viral infection, and even a substantial percentage of patients with acute bacterial sinusitis -- up to 47% in one study (Sinus and Allergy Health Parnership. Antimicrobial treatment guidelines for acute bacterial rhinosinusitis. Otalyngol Head Neck Surgery 2000;123:S1-S32).
  • Different specialties approach the problem differently. For example, in one study ENT physicians were far more likely than family practice physicians to: order sinus x-rays; use topical decongestants; and use saline (salt water) nasal irrigation (Werning JW, et al. Physician specialty is associated with differences in the evaluation and management of acute bacterial rhinosinusitis. Arch Otolaryngol Head Neck Surg 2002;128:123-130.) In this study there were no significant differences in diagnosis and management by family physicians and general internists.

A given patient with upper airway inflammation -- visiting a family practice physician, an internist, an ENT physician, an allergist, and a pulmonary specialist -- could well end up on 5 different regimens for the same symptoms! In fact, all five specialties do get involved in treating patients with rhinitis/sinusitis/chronic cough. To this end, throughout my web site you will find links to other web sites, articles, and books authored by or for the different groups of treating physicians.

It is common for patients with chronic cough to be referred to another physician, which explains why pulmonary specialists see so many patients with this complaint. Allergists also get a lot of referrals for this problem. Allergists and pulmonologists refer cough patients as well, especially to ENT physicians. And ENT physicians who cannot help a problem through surgical means will often refer the patient to a pulmonary specialist, allergist, or back to the original primary care doctor.

The result is that patients with chronic cough of more than a month's duration will invariably see at least two different doctors, sometimes three. The root problem is that chronic cough can be difficult to both diagnose (especially if there is more than one cause) and treat (treatment is often a process of trial and error).

What is the relationship of rhinosinusitis and asthma?

In a word, complex. Asthma is a disease manifested by excessive mucus production in the lungs. In fact most asthmatics also have mucus in their sinuses. Usually this is from a viral infection or allergy, the same conditions that most commonly trigger an asthma attack. Thus patients 'with asthma' will commonly also have inflammation of their sinuses.

On the other hand, rhinitis and sinusitis can be the triggers of asthma. That is, patients without any asthma history can develop asthma AS A RESULT OF rhinitis and/or sinusitis. Simplistically, this seems to occur from constant dripping of mucus into the lungs, triggering an asthma reaction. The actual mechanism, however, is unknown. (See Guerra S, et al. Rhinitis as an independent risk factor for adult-onset asthma. J Allergy Clin Immunol 2002;109:419-25;
Epidemiologic evidence for asthma and rhinitis comorbidity, by Leynaert, et al.)

Sometimes asthma is treated maximally and still doesn't get better. When this happens, we will often check to see if the sinuses are 'impacted' or blocked to the extent that they are continuing to cause asthma symptoms despite maximal treatment. Sinusitis is definitely one of the conditions doctors need to evaluate in cases of intractable asthma (see Hidden factors in asthma, by Somerville LL. Allergy Asthma Proc 2001;22:341-45).

Note that DRUGS USED TO TREAT ASTHMA are different from DRUGS FOR RHINOSINUSITIS, with one exception: steroids. Steroids, also called 'corticosteroids', include the drugs prednisone and methylprednisolone [Medrol Dose Pak]). Steroids are commonly used for both severe asthma and protracted rhinosinusitis.

How is sinusitis diagnosed?

Symptoms and physical exam may suffice to make the diagnosis. Facial pain, purulent nasal discharge, fever, headache, chronic cough -- all suggest the diagnosis and warrant treatment. When symptoms are not clear cut, physicians will often order x-rays of the sinuses. There are two types -- conventional sinus x-rays, now infrequently used and considered by some as obsolete; and sinus CT scan, which gives a far better picture of the sinues than conventional x-ray. An abnormal sinus CT scan, along with compatible symptoms will suffice to make the diagnosis. A third way is for an ENT surgeon to put a probe into the sinus openings (going through the nose) to see if pus is coming out of the openings (other physicians generally do not do this procedure).

What is an example of specific treatment of chronic cough due to upper airway inflammation?

A 43-year-old woman was evaluated for chronic cough of a month's duration. It started with a 'cold', for which she took OTC medication. When the cold didn't get better, she was given a course of the antibiotic azithromycin, by her primary care physician. The cough improved a little, but when the antibiotic stopped the cough recurred. She was then referred.

She gave no history of asthma or any respiratory disease. She is a non-smoker and her husband does not smoke. She gave no symptoms to suggest stomach acid reflux. She is on blood pressure medication, but not the type typically associated with cough.

Her cough is mainly dry, i.e., not productive of mucus. Yet she often feels mucus "dripping down the back of my throat," as she explaied. She is not ill and is able to work full time as a librarian. However, the cough is quite bothersome, and colleagues at work have commented on it often. She is at her 'wit's end' about what to do.

Exam is mostly unremarkable. There is minimal nasal congestion but she can breathe through her nose. There is no sinus tenderness. Her ears are normal and her lungs are clear. A chest x-ray two weeks ago was read as normal.

Diagnosis: Probable rhinosinusitis, starting out as a viral infection, now complicated by inflammation in the sinuses and back of the nose, dripping into her lungs and causing chronic cough.

1) Augmentin, 875 mg twice a day for 10 days, in case there was any on-going bacterial process.
2) Prednisone, 20 mg twice a day for three days, followed by 20 mg once a day for three days, followed by 10 mg a day for three more days, then stop the drug. A short course of prednison is virtually free of side effects and is an excellent drug for chronic inflammation.
I also recommended an over the counter decongestant, such as sudafed, twice a day, and a hot steamy shower once a day, with expectoration of as much nasal mucus as possible.

She returned a week later 'all better.' At that point she was almost finished with the prednisone and antibiotic, and had stopped the OTC decongestant. I told her to call me if the cough recurs.

What about treatment failures?

These, unfortunately, are not uncommon.
A 48-year-old man was evaluated for chronic cough "for the past three months." He gave a history of 'sinus infections' yearly for several years, but said "this is the worst." He had already had two courses of antibiotics, each for 10 days, with no improvement. He had not been prescribed prednisone.

I put him on an aggressive course of therapy, and told him if he was no better in a week, that I would do a CT of the sinsuses and perhaps refer him to an ENT surgeon. I stared him on antibiotic Levaquin 500 mg a day, plus prednisone at 20 mg twice a day for a full week. I also gave him a nasal steroid medication to use daily (Flonase), AND a decongestant to use in case there was an allergic component (Claritin-24).

He returned the following week minimally improved. As planned, I sent him for a sinus CT scan. The scan showed impacted maxillary sinuses with 'air-fluid' levels, indicating severe chronic sinusitis, plus extensive mucus in his sphenoid and ethmoid sinuses. There sinuses were so blocked that antibiotics and steroids and decongestants simply could not be effective. He was sent to an ENT surgeon who recommeneded surgery to relieve the blocked sinuses.

What is the role of surgery in chronic sinusitis?

Surgery is reserved for those patients who don't respond to extensive treatment with medication, such as the above patient. 'Extensive treatment' means, usually, at least three weeks of antibiotics, steroid medication (prednisone or methylprednisolone), and daily decongestants. Patients are considered for surgery if they remain symptomatic and a CT scan shows the sinuses are not draining. At that point the decision regarding surgery will be up to the patient and his or her ENT physician (of all physicians who treat sinusitis, only ENT physicians operate).

For more information on sinus surgery see When should surgery be considered?

How successful is sinus surgery?

Statistics are hard to come by, for two principal reasons: there are multiple types of surgery, depending on the nature of the disease, and "success" depends on who you ask. A 50% reduction in patient symptoms may be deemed successful by some patients/doctors, and a failure by other patients/doctors. Suffice to say that sinus surgery is not usually 100% successful in alleviating all symptoms of chronic sinusitis.

The most common type of surgery is probably endoscopic surgery for maxillary sinusitis (the sinuses behind the cheek bones). One surgeon acknowledged that "a significant number of patients have persistent maxillary symptoms after one or more endoscopic sinus operations," and identified 10 different reasons (see Top 10 reasons for endoscopic maxillary sinus surgery failure, by WJ Richtsmeier. Laryngoscope 2001;111:1952-56.)

Web Links & References / Table of Drugs used to treat rhinitis & sinusitis / 10 Common Myths, Misconceptions, Errors and Mistakes about Chronic Cough / Chronic throat clearing

Index to all of Dr. Martin's web sites
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Copyright © 2008, Lawrence Martin, M.D.



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