Postnasal Drip: Diagnosis and Treatment

Educational Objectives

The goal of this program is to improve diagnosis and management of postnasal drip. After hearing and assimilating this program, the clinician will be better able to:

1. Identify common conditions linked to postnasal drip.
2. Summarize the effects of age and otolaryngologic conditions on mucociliary clearance rates.

Summary

Postnasal drip: is a subjective symptom without a clear cause or established method for diagnosis; various theories suggest it may be related to ciliary dysfunction, excessive mucus production, airway irritation, or heightened body awareness; however, there is no definitive way to measure it, and diagnosis relies solely on patient reports; some individuals may be predisposed to developing postnasal drip, which could offer insights into its origins

Causes: postnasal drip is commonly reported in patients with cystic fibrosis, primary ciliary dyskinesia, allergic rhinitis, and nasal polyps, suggesting links to mucus clearance issues, inflammation, or airway sensitivity; while its exact cause remains unclear, some studies have attempted objective characterization using rhinoscopy to examine airway inflammation and drainage or by measuring mucociliary clearance to determine if a threshold exists for postnasal drip symptoms; Tarmizi et al (2023) used rhinoscopy to identify possible clinical correlations; the only significant finding was the presence of secretions in the posterior nasal cavity, which had a sensitivity of 78.3% and specificity of 44.7%; other factors (eg, redness, hemorrhagic spots in the nasopharynx) showed no significant correlation with postnasal drip

Mucociliary clearance: is the process by which cilia move mucus through the nasal passages; it can be measured using in vivo and in vitro methods; the saccharin transit test (in vivo) involves placing saccharin in the nasal passage and timing how long it takes for a patient to taste sweetness; fluorescent particle tracking (in vitro) observes particle movement on epithelial cells; mucociliary clearance peaks in middle age and is slower in children and older adults; clearance speeds average 11.1 mm/min in children and 12.7 mm/min in adults, with a noticeable decline at >60 yr of age; patients with postnasal drip experience significantly prolonged mucociliary transit times compared with healthy individuals; their mucus is also 10 times more viscous than normal; however, their mucociliary clearance times return to normal levels after treatment, suggesting a correlation between ciliary function and postnasal drip symptoms

Cystic fibrosis: is caused by a mutation in the chloride transporter; this condition leads to abnormally thick mucus, which severely impairs mucociliary clearance; transit speeds average 1.2 μm/min, a drastic reduction compared with healthy individuals; as a result, patients with cystic fibrosis experience significantly more postnasal drip

Allergic rhinitis: is associated with postnasal drip because of increased histamine and cysteinyl leukotriene secretion, which results in mucus hypersecretion; additionally, allergic individuals show heightened sensitivity to major basic protein (MBP), a molecule released by eosinophils; MBP can cause ciliary stasis in allergic individuals, which impairs mucociliary clearance, whereas nonallergic individuals experience minimal effects; this ciliary dysfunction may explain the accumulation of secretions and the increased postnasal drip observed in patients with allergies

Upper respiratory infections: can lead to postnasal drip related to ciliocytophthoria, a condition in which epithelial cells fragment and form vacuoles; this damage can persist for 2 to 10 wk after the infection resolves, potentially explaining prolonged symptoms; additionally, genetic factors play a role, specifically variations in the TAS2R38 bitter taste receptor, which regulates nitric oxide (NO) production; NO increases ciliary beat frequency, which helps to clear excess mucus; individuals with genetically lower NO production experience reduced ciliary activity, making them more susceptible to postnasal drip after upper respiratory infections

Noninfectious, nonallergic rhinitis: (eg, gustatory or neurologic rhinitis) is associated with elevated neuropeptides; TRPV1 receptors respond to capsaicin (from chili peppers), which may help reduce neuropeptide release and improve symptoms

Laryngopharyngeal reflux: is associated with postnasal drip, indicating that inflammation, airway hypersensitivity, and neurogenic factors may contribute to the condition beyond sinonasal diseases

Sinonasal outcome test (SNOT): postnasal drip can be assessed using the SNOT, a subjective, patient-reported scale that ranges from 0 (no symptoms) to 5 (very bothersome symptoms); the SNOT-22 questionnaire includes 22 questions, with postnasal discharge as one of the key markers; patients identify their top 5 most bothersome symptoms, which helps physicians track symptom progression and treatment effectiveness

Challenges in assessing postnasal drip: studies have examined how accurately patients can report their experiences; study from European Rhinologic Society found that patients struggle to consistently assess their symptoms, especially postnasal drip; unlike loss of smell, nasal blockage, or facial pressure, which correlate well with patients’ perceived symptom control, postnasal drip does not follow this pattern; some patients rated their symptoms as severe but well-controlled, while others reported mild symptoms as poorly controlled; this inconsistency raises concerns about the reliability of self-reported data and highlights the need for more objective measures of postnasal drip

Treatment: while placebo interventions improve SNOT scores, they seem to have little effect on postnasal drip specifically; a review of studies from the last 10 yr highlights various treatment options for postnasal drip across different conditions; for chronic rhinosinusitis, effective treatments include revision endoscopic sinus surgery, posterior nasal nerve ablation, and ivacaftor (typically used for treatment of cystic fibrosis); studies on chronic rhinosinusitis with nasal polyps show that omalizumab significantly reduces postnasal drip symptoms; fluticasone nasal sprays, dupilumab, and functional endoscopic sinus surgery also yield moderate improvements; for allergic rhinitis, posterior nasal nerve resection, montelukast, and dupilumab yield positive results; for laryngopharyngeal reflux, omeprazole and magnetic sphincter augmentation help alleviate symptoms

Readings

Bustamante-Marin XM, Ostrowski LE. Cilia and mucociliary clearance. Cold Spring Harb Perspect Biol. 2017;9(4):a028241. doi:10.1101/cshperspect.a028241; Kurbatova P, Bessonov N, Volpert V, et al. Model of mucociliary clearance in cystic fibrosis lungs. J Theor Biol. 2015;372:81-88. doi:10.1016/j.jtbi.2015.02.023; Mikolajczyk M, Janukowicz K, Majewska E, Baj Z. Impact of allergic rhinitis on nasal mucociliary clearance time in children. Int Arch Allergy Immunol. 2019;179(4):297-303. doi:10.1159/000499740; Nakajima T, Nagano T, Nishimura Y. Retrospective study of the effects of post-nasal drip symptoms on cough duration. In Vivo. 2021;35(3):1799-803. doi:10.21873/invivo.12440; Smallwood D, Ledford D, Kennedy D, et al. Postnasal Drip. J Allergy Clin Immunol Pract. 2024;12(6):1472-1478. doi:10.1016/j.jaip.2024.04.030; Tarmizi NE, Hamizan AW, Ng CS, et al. The nasal endoscopic features of postnasal drip: a cross sectional study. Int Arch Otorhinolaryngol. 2023;28(1):e95-e100. doi:10.1055/s-0043-1767799; Weinberger M, Hurvitz M. Diagnosis and management of chronic cough: similarities and differences between children and adults. F1000Res. 2020;9:F1000. doi:10.12688/f1000research.25468.1.

Disclosures

For this program, members of the faculty and the planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Smallwood was recorded at the 2025 Symposium Allergy and Immunology, held January 17-18, 2025, in Tampa, FL, and presented by USF Health Division of Allergy and Immunology, Internal Medicine and Pediatrics. For information about upcoming CME activities from this presenter, please visit Health.usf.edu/cpd. Audio Digest thanks the speakers and presenters for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0.75 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0.75 CE contact hours.

Lecture ID:

OT580801

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.

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