Post-nasal drip syndrome—a symptom to be sniffed at?
Introduction
The literature is sharply divided in its use of the term PNDS. Most American authors use the term widely and find a very high incidence in patients reporting to the cough clinic. In Europe PNDS is much less frequently recognized. Could the differences between these societies reflect the different incidence of PNDS? PNDS is not mentioned in much of the standard literature; indeed, the Oxford Handbook of Clinical Specialities goes straight from post-menopausal to post-natal. It is becoming increasingly recognized that the localization of sensation within the thorax and upper airways is poor and that as our understanding of the causes of cough evolves symptoms such as airway hyperresponsiveness may have their origin in oesophageal disease. With the developments of impedance technology post-nasal symptoms may be found to be related to laryngopharyngeal reflux rather than any pure post-nasal problem.
The reported incidence of post-nasal drip syndrome (PNDS) varies widely within the chronic cough literature [1] (Table 1). It seems most unlikely that these large differences in incidence in PNDS are only due to different patient characteristics. It suggests a fundamental difference in the definition of PNDS or, indeed, whether PNDS actually exists as a separate entity.
Collins Dictionary of Medicine defines a syndrome as “a unique combination of sometimes apparently unrelated symptoms or signs forming a distinct clinical entity”. In contrast ‘a symptom is a subjective perception suggesting a bodily defect or malfunction’. Thus, whilst there is no denying that some patients with chronic cough complain of the sensation of ‘something running down the back of the throat’ for PNDS to qualify as a syndrome there should be associated other features, or physical signs. Ideally, the triad of chronic cough, post-nasal drip and observable retropharyngeal mucus should consistently occur together and be ‘the distinct effects of a common cause’.
Section snippets
Rhinosinusitis and chronic cough
A number of clinical syndromes are associated with rhinosinusitis and chronic cough [2]. However, a distinction should be made between those conditions where the rhinosinusitis is merely part of a generalized abnormality and isolated rhinosinusitis. In primary ciliary dyskinesia rhinosinusitis may be the presenting complaint [3] but is the disease in the nasopharynx the cause of the chronic cough? Patients almost invariably have a significant degree of bronchiectasis and the productive cough is
Pathophysiology
The associated features of PNDS such as throat clearing and hoarseness are frequently associated with other causes of cough, particularly reflux disease [5]. Symptoms are poorly localized within the upper airways. Laryngeal inflammation may be easily detected in patients with reflux disease. It would be unsurprising were patients with reflux not to have post-nasal inflammation.
A further problem with the description of PNDS as a cause of cough is in the pathological mechanisms leading to the
Epidemiology
The incidence of PNDS as a reported diagnosis for chronic cough varies enormously [8]. A pattern emerges, however, in that those clinics reporting the highest incidence of PNDS come from the United States, whereas it is much less frequently reported in the European experience. In a study by Proctor & Gamble (US980399, Dr David Hull, personal communication) patients were asked by telephone interview whether they suffered post-nasal drip during an episode of cough/cold in the preceding 6 months.
Treatment
One of the major points arguing for the treatment of PNDS as a syndrome causing chronic cough is the response to specific pharmacological therapy [9]. This assumption, however, is incorrect, since the drugs advocated for PNDS due to perennial rhinitis or post-viral upper respiratory tract infection are the older generation sedating antihistamines or antihistamine/decongestant combinations [7]. Such medications are anything but specific. The fact that these drugs are sufficiently lipophilic to
Conclusion
Post-nasal drip syndrome is a symptom masquerading as a syndrome. It varies widely across different societies and there is no objective test. The term rhinitis or rhinosinusitis should be used in preference.
References (21)
Epidemiology of cough
Pulmonary Pharmacol Ther
(2002)- et al.
Management of common voice problems: Committee report
Otolaryngol Head Neck Surg
(2002) - 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) - et al.
Chronic persistent cough. Experience in diagnosis and outcome using an anatomic diagnostic protocol
Chest
(1989) - et al.
Chronic cough with a history of excessive sputum production. The spectrum and frequency of causes, key components of the diagnostic evaluation, and outcome of specific therapy
Chest
(1995) - et al.
A pathogenic triad in chronic cough: asthma, postnasal drip syndrome, and gastroesophageal reflux disease
Chest
(1999) - et al.
The diagnosis and management of chronic cough
Eur Respir J
(2004) - et al.
Cough 2: Chronic cough in children
Thorax
(2003) - et al.
Baseline inflammation in the lower airways of allergic rhinitis subjects compared to normal sobjects
Eur Respir J
(2002) Sensory neurophysiology of the cough reflex
J Allergy Clin Immunol
(1996)
Cited by (72)
Chronic cough is complicated
2023, Annals of Allergy, Asthma and ImmunologyWAO-ARIA consensus on chronic cough - Part II: Phenotypes and mechanisms of abnormal cough presentation — Updates in COVID-19
2021, World Allergy Organization JournalBurden of Specialist-Diagnosed Chronic Cough in Adults
2020, Journal of Allergy and Clinical Immunology: In PracticeCitation Excerpt :Guidelines developed by professional organizations provide systematic approaches to the assessment20 and management of CC,3,4,21-25 which help identify many of the treatable causes of CC. The 3 most common causes of CC are upper airway cough syndrome (previously referred to as postnasal drip syndrome),26 asthma,27 and gastroesophageal reflux disease (GERD).28 The nomenclature of CC without a known cause or refractory to treatment includes refractory cough (1.3%), unexplained cough (0.9%), and idiopathic cough (0.7%).2
Should the Reflex Be Reflux? Throat Symptoms and Alternative Explanations
2015, Clinical Gastroenterology and HepatologyCough in interstitial lung disease
2015, Pulmonary Pharmacology and TherapeuticsAdult and paediatric cough guidelines: Ready for an overhaul?
2015, Pulmonary Pharmacology and Therapeutics