Use of topical nasal therapies in the management of Chronic rhinosinusitis

Chitosan-based crosslinking for controlled topical drug release in rhinosinusitis

KEY POINTS

Chitosan is a promising drug delivery vector for therapeutics owing to its biocompatibility. Once crosslinked with chitosan, prolonged drug release was noted regardless of hydrophilicity. Hydrophilic drugs may require different strategies to obtain a sustained release profile.

[Modern management of chronic rhinosinusitis]

Chronic rhinosinusitis is a common disease. Due to the significant reduction of the quality of life, possible serious complications and economic consequences, a sufficient therapy is essential. With the entry of biologics into the treatment of chronic rhinosinusitis, relevant innovations have emerged in recent years. This article is aimed at providing an up-to-date overview of the conservative and surgical treatment options for chronic rhinosinusitis.

The impact of chronic rhinosinusitis on COVID-19 risk and outcomes: A systematic review and meta-analysis

Background

The impact of chronic rhinosinusitis (CRS) and subsequent steroid therapy on acquiring COVID-19 and severe outcomes remains controversial. Therefore, we conducted this systematic review and meta-analysis to provide cumulative evidence regarding the risk of COVID-19 and the impact of steroid therapy, length of hospital stay, mechanical ventilation, and mortality among CRC patients.

Methods

We conducted a comprehensive electronic search strategy using the relevant keywords. The outcomes and risk factors of COVID-19 in CRS patients was estimated and compared to a healthy control group when applicable.

Results

A total of seven studies were included, with an estimated prevalence of 6.5% (95% confidence interval (CI): 2.5-15.7) for COVID-19 in the CRS group. COVID-19 prevalence did not differ between CRS and controls (odds ratio (OR): 0.92; 95%CI: 0.84-1.01; p = 0.08). Moreover, using steroid/immunosuppressive therapy did not significantly increase the risk of acquiring COVID-19 in CRS patients compared to the control group (OR: 3.31; 95%CI: 0.72-15.26; p = 0.12). Length of hospital stay, mechanical ventilation, and mortality rates were comparable between the two groups. Furthermore, we found that male sex, cardiovascular morbidity, renal diseases, and hypertension were inversely associated with COVID-19 infection (p < 0.01).

Conclusion

CRS had a neutral effect on acquiring COVID-19 and developing severe outcomes. However, further studies are needed.

Computational investigation of nasal surface coverage from squeeze bottle and Neti Pot saline irrigation flow

BACKGROUND AND OBJECTIVE

Nasal saline irrigation is a common therapy for inflammatory nasal and paranasal disease or for managing post nasal and sinus surgery recovery. Two common irrigation devices include the netipot and squeeze bottles, where anecdotally, these devices alleviate congestion, facial pain, and pressure. However, a quantitative evaluation of these devices' performance and the fluid dynamics responsible for the irrigation distribution through the nose is lacking. This study tracked the liquid surface coverage and wall shear stresses during nasal saline irrigation produced from a Neti Pot and squeeze bottle.

METHODS

This study used transient computational fluid dynamics (CFD) simulations to investigate the saline irrigation flow field in a subject-specific sinonasal model. The computational nasal cavity model was constructed from a high-resolution computed tomography scan (CT). The irrigation procedure applied a head position tilted at 90° forward using an 80 ml squeeze bottle and 120 ml Neti Pot.

RESULTS

The results from a single sinonasal model demonstrated that the Neti Pot irrigation was more effective in delivering saline solution to the nasal cavity on the contralateral side of irrigation due to typically larger volumes but at the expense of reduced flow and shearing rates, as the flow entered under gravitational forces. The squeeze bottle irrigation provided greater surface coverage on the side of irrigation.

CONCLUSIONS

The results from the single patient model, demonstrated the Neti Pot increased surface coverage in the paranasal sinuses. Reducing the jet diameter may aid the direct targeting of a specific region at the side of irrigation by preventing the impingement of the jet to the nasal passage surface and redirection of the flow. Evaluating this performance across a wider cohort of patients can strengthen the findings.

Atopy as a specific predictor of response to systemic and local steroid therapy in patients with chronic rhinosinusitis without nasal polyps

<b>Introduction:</b> Studies on the pathophysiology of chronic rhinosinusitis have shown an effect of IgE antibodies on the course of the disease, as well as the effectiveness of treatment. Steroid therapy remains the most prevailing method of CRS treatment. </br></br> <b>Aim: </b>The aim of our study was to determine the clinical response to systemic and local steroid therapy in patients with CRSsNP depending on the total IgE antibody serum concentration. </br></br> <b>Material and methods:</b> A total of 92 patients with CRSsNP took part in the study, where they were divided randomly into 2 groups. In group I, the patients received fluticasone propionate 800 mcg/day intranasally for 12 weeks. Patients in group II were treated with prednisone at a dose of 0.5 mg/kg/day, given orally, for 7 consecutive days and continued by another week with decreasing dosage. Both groups were evaluated prior to and following treatment using the TSS score of CRS clinical symptoms, the endoscopic Lund-Kennedy scale and the Lund-Mackay CT staging of chronic rhinosinusitis. Statistical analy-sis of the effectiveness of treatment was carried out in subgroups according to the total IgE serum concentrations obtained before treatment. </br></br> <b>Results:</b> Both groups of patients achieved statistically significant improvement in the TSS evaluation, as well as in endosco-pic and CT imaging findings. In patients with a total IgE serum concentration over 100 IU/ml systemic steroid therapy sho-wed significantly greater effect on the relief of CRS symptoms in the TSS score than intranasal steroid therapy. Analogous differences in the effectiveness of both methods were not found in patients with a normal total IgE serum concentration (<100 IU/ml). </br></br> <b>Conclusions:</b> A short course of systemic steroid therapy is more effective than local treatment in relieving of CRS symptoms in patients with CRSsNP with elevated serum concentration of IgE antibodies. Atopy may be considered a specific predictor of response to steroid therapy in the treatment of chronic rhinosinusitis.

Precision Medicine in Chronic Rhinosinusitis: Where Does Allergy Fit In?

Chronic rhinosinusitis (CRS) is a clinical syndrome stemming from persistent inflammation of the sinonasal mucosa. Phenotypically, it is traditionally and widely described according to the presence or absence of polyps. While this distinction is simple to use, it has little bearing on prognosis and treatment, for CRS is essentially an inflammatory disease resulting from dysregulated interaction between a multitude of host and environmental factors. Allergy is merely one of them and, like many of the proposed aetiologies, has been subject to much debate which will be discussed here. As our understanding of CRS continues to evolve, previous so-called conventional wisdom about phenotypes (e.g. CRS with nasal polyps is associated with Type 2 inflammation) is being challenged, and new phenotypes are also emerging. In addition, there is growing interest in defining the endotypes of CRS to deliver precise and personalised treatment, especially pertaining to the development of biologics for the group of severe, difficult-to-treat CRS patients. A proposed model of precision medicine tailored to management of CRS will also be introduced to readers, which can be continually modified to adapt to new discoveries about this exciting condition.

Efficacy and safety evaluation of a hypertonic seawater solution enriched with manganese and copper salts

Background: Nasal irrigation is commonly recommended as an adjuvant treatment for blocked nose. In the present study, the safety and efficacy profile of Stérimar Blocked Nose (SBN), a hypertonic seawater solution enriched with manganese and copper salts, has been evaluated on nasal epithelium, in vitro. Methodology: 3D reconstituted human nasal epithelium tissue model, MucilAir™, has been used to investigate the safety of SBN on nasal epithelium by measuring trans-epithelial electrical resistance (TEER), cytotoxicity (lactate dehydrogenase (LDH) release) and phlogosis-related effects (interleukin-8 secretion). Efficacy assessment was measured by ciliary beat frequency (CBF), mucociliary clearance (MCC) and antimicrobial activities (against Staphylococcus aureus and Pseudomonas aeruginosa). Results: Four-day SBN treatment did not compromise the nasal epithelium integrity as TEER values were over the tissue integrity limit. SBN treatment did not exert cytotoxic (LDH release) or pro-inflammatory effects (IL-8 secretion). SBN treatment significantly increased the CBF and MCC rates compared to untreated cells. SBN treatment exerted a bactericidal effect on S. aureus and P. aeruginosa cultures, whereas seawater not enriched in copper and manganese had only a bacteriostatic effect. Conclusions: The results demonstrate that SBN is a safe formula for use on human nasal epithelium. The results also suggest a better potential therapeutic role for SBN in comparison to not-enriched seawater when used to control nasal congestion and inhibit bacterial growth which may cause nasal congestion.

Management of patients with chronic rhinosinusitis during the COVID-19 pandemic-An EAACI position paper

BACKGROUND

Chronic rhinosinusitis is regarded as a chronic airway disease. According to WHO recommendations, it may be a risk factor for COVID-19 patients. In most CRSwNP cases, the inflammatory changes affecting the nasal and paranasal mucous membranes are type-2 (T2) inflammation endotypes.

METHODS

The current knowledge on COVID-19 and on treatment options for CRS was analyzed by a literature search in Medline, Pubmed, international guidelines, the Cochrane Library and the Internet.

RESULTS

Based on international literature, on current recommendations by WHO and other international organizations as well as on previous experience, a panel of experts from EAACI and ARIA provided recommendations for the treatment of CRS during the COVID-19 pandemic.

CONCLUSION

Intranasal corticosteroids remain the standard treatment for CRS in patients with SARS-CoV-2 infection. Surgical treatments should be reduced to a minimum and surgery preserved for patients with local complications and for those with no other treatment options. Systemic corticosteroids should be avoided. Treatment with biologics can be continued with careful monitoring in noninfected patients and should be temporarily interrupted during the course of the COVID-19 infection.

Inhalations with Brine Solution from the 'Wieliczka' Salt Mine Diminish Airway Hyperreactivity and Inflammation in a Murine Model of Non-Atopic Asthma

Inhalations with brine solutions are old but underestimated add-ons to pharmacological treatments of inflammatory lung diseases. Although widely used, not all features underlying their action on the respiratory system have been explored. The aim of the present study was to elucidate the mechanism of the beneficial action of inhalations of brine solution from the 'Wieliczka' Salt Mine, a Polish health resort, in a murine model of non-atopic asthma. Asthma was induced in BALB/c mice by skin sensitization with dinitrofluorobenzene followed by an intratracheal challenge of cognate hapten. All animals underwent 12 inhalation sessions with brine solution, pure water or physiological saline. Control mice were not inhaled. We found that brine inhalations reduced, as compared to non-inhaled mice, the typical asthma-related symptoms, like airway hyperreactivity (AHR), the infiltration of pro-inflammatory cells into the bronchial tree, and the inflammation of the airways at the level of pro-inflammatory cytokines IL-1α, IL-1β and IL-6. The level of the anti-inflammatory IL-10 was elevated in brine-inhaled mice. Inhalations with pure water increased AHR, whereas saline had no influence, either on AHR or cytokine concentrations. These observations indicate that inhalations with a brine solution from the 'Wieliczka' Salt Mine diminish the asthma-related symptoms, mostly by reducing the inflammatory status and by decreasing AHR.

Positionspapier: Empfehlungen zur Behandlung der chronischen Rhinosinusitis während der COVID-19-Pandemie im deutschen Gesundheitssystem – Empfehlungen des Ärzteverbandes Deutscher Allergologen (AeDA) und der Deutschen Gesellschaft für HNO-Heilkunde, Kopf- und Halschirurgie (DGHNO-KHC) – Diese Empfehlungen basieren auf dem EAACI Positionspapier „Treatment of chronic RhinoSinusitis with nasal polyps (CRSwNP) in the COVID-19 pandemics – An EAACI Position Paper”, Allergy, 2020 und wurden auf die Situation im deutschen Gesundheitswesen angepasst

Hintergrund  Von der chronischen Rhinosinusitis (CRS) sind weltweit etwa 5–12 % der Allgemeinbevölkerung betroffen. Die CRS gilt als chronische Atemwegserkrankung, die nach den Empfehlungen der WHO ein Risikofaktor für COVID-19-Patienten sein kann. Die entzündlichen Veränderungen der Nasenschleimhäute bei chronischer Rhinosinusitis mit Nasenpolypen (CRSwNP) sind in den meisten Fällen vom Entzündungsendotyp 2 (T2).

Methoden  Der aktuelle Wissensstand sowohl zu COVID-19 als auch zu den Behandlungsmöglichkeiten von CRSwNP wurde durch eine Literaturrecherche in Medline, Pubmed, internationalen Leitlinien, der Cochrane Library und im Internet analysiert.

Ergebnisse  Auf Grundlage der internationalen Literatur, der aktuellen Empfehlungen der WHO und anderer internationaler Organisationen sowie der bisherigen Erfahrungen gab ein Expertengremium von EAACI und ARIA Empfehlungen für die Behandlung von CRSwNP während der COVID-19-Pandemien.

Schlussfolgerung  Intranasale Kortikosteroide stellen die Standardbehandlung für CRS bei Patienten mit einer SARS-CoV-2-Infektion dar. Chirurgische Behandlungen sollten auf ein Minimum reduziert werden und nur bei Patienten mit lokalen Komplikationen und solchen, für die keine anderen Behandlungsmöglichkeiten bestehen, durchgeführt werden. Systemische Kortikosteroide sollten bei COVID-19-Patienten vermieden werden. Die Behandlung mit Biologika kann bei nicht infizierten Patienten unter sorgfältiger Überwachung fortgesetzt werden und sollte während einer SARS-CoV-2-Infektion vorübergehend unterbrochen werden.

In-office Placement of Mometasone Furoate Sinus Implants for Recurrent Nasal Polyps: A Pooled Analysis

Background

A mometasone furoate (MF) sinus implant (1350 mcg) was evaluated in 2 randomized controlled trials (RCTs) in 400 adults with nasal polyps (NP) who were candidates for revision endoscopic sinus surgery (RESS). We conducted a pooled analysis to evaluate the efficacy of MF implant in specific subgroups of NP patients.

Methods

Pooled data from 2 RCTs for 375 patients were analyzed across prespecified subjective and objective end points through day 90.

Results

At day 90, patients receiving implants and MF nasal spray (MFNS) experienced significant improvements in nasal obstruction/congestion (NO/C) score ( P = .0095), bilateral polyp grade (BPG, P = .0008), and ethmoid sinus obstruction ( P < .0001) compared to control using MFNS alone. Fewer treatment than control patients remained candidates for RESS (41.0% vs 69.3%, P < .0001). All subgroups experienced significant treatment effects, except NO/C in smokers ( P = .0509) and patients without altered smell ( P = .1873). Subgroups without asthma and with only 1 prior ESS experienced largest treatment effect on NO/C, and those with recent surgery <24 months and BPG >5 showed largest effect on endoscopic end points and RESS. Control patients with ESS <24 months were at 7 times highest risk for RESS ( P < .0001). One (0.4%) patient experienced implant-related serious adverse event (epistaxis).

Conclusion

On pooled analysis, MF implants with MFNS showed more favorable results than MFNS alone across several subjective and objective end points at day 90 and may play an important role in management of NP patients, especially those who have allergic rhinitis, expanded polyposis, altered smell, or had most recent ESS < 24 months.

P-glycoprotein and chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a heterogeneous definition that includes different disease states that usually are associated with abnormal inflammatory responses. Besides being prevalent, the mechanisms involved in its pathogenesis are not clear and there are few therapeutic options with tolerable side effects. P-glycoprotein (P-gp) is an efflux pump responsible of extruding xenobiotics and cellular metabolites from multiple cell types. It has been widely studied in the cancer field, due to its ability to confer resistance to chemotherapy. It also promotes Type 2 helper T-cell polarizing cytokine secretion in CRS and may represent a potential target to differentiate subtypes of CRS and personalize treatment. This state-of-the-art review explores current knowledge on the participation of P-gp in the pathogenesis of CRS, the P-gp inhibition as a novel targeted therapeutic strategy and the exosomal P-gp test, a non-invasive biomarker that can represent an important advance in the field of rhinology.

Evaluation of a steroid releasing sinus implant for the treatment of patients undergoing frontal sinus surgery for chronic rhinosinusitis

INTRODUCTION

Management of the frontal sinus places great demands on the otolaryngologist. Given that the fronto-ethmoidal region is susceptible to recurrent inflammation, scarring, and stenosis, maintaining long-term patency of the frontal sinus is a difficult challenge. Oral and topical anti-inflammatory therapy, post-operative stenting, and 'home-brew' drug elution have been used for the treatment of the frontal sinus with mixed success. Recently an implant has been approved for post-operative placement into the frontal recess. This implant provides reliable and consistent steroid drug elution to address inflammation of the frontal recess secondary to chronic sinusitis. Areas covered: This review discusses the development and application of steroid eluting implants in the postoperative care of patients with chronic frontal sinusitis. All randomized controlled trials evaluating steroid eluting implants are discussed. Relevant supporting material discussing background, economics, safety are included. Expert commentary: Steroid eluting implants fulfill a unique niche in the treatment following frontal sinus surgery. They are shown to decrease the need for post-operative interventions and improve outcomes in patients with chronic sinusitis. There is significant potential for growth in the use of steroid eluting implants.

Chronic rhinosinusitis pathogenesis

There are a variety of medical conditions associated with chronic sinonasal inflammation, including chronic rhinosinusitis (CRS) and cystic fibrosis. In particular, CRS can be divided into 2 major subgroups based on whether nasal polyps are present or absent. Unfortunately, clinical treatment strategies for patients with chronic sinonasal inflammation are limited, in part because the underlying mechanisms contributing to disease pathology are heterogeneous and not entirely known. It is hypothesized that alterations in mucociliary clearance, abnormalities in the sinonasal epithelial cell barrier, and tissue remodeling all contribute to the chronic inflammatory and tissue-deforming processes characteristic of CRS. Additionally, the host innate and adaptive immune responses are also significantly activated and might be involved in pathogenesis. Recent advancements in the understanding of CRS pathogenesis are highlighted in this review, with special focus placed on the roles of epithelial cells and the host immune response in patients with cystic fibrosis, CRS without nasal polyps, or CRS with nasal polyps.

Non-diluted seawater enhances nasal ciliary beat frequency and wound repair speed compared to diluted seawater and normal saline

Background

The regulation of mucociliary clearance is a key part of the defense mechanisms developed by the airway epithelium. If a high aggregate quality of evidence shows the clinical effectiveness of nasal irrigation, there is a lack of studies showing the intrinsic role of the different irrigation solutions allowing such results. This study investigated the impact of solutions with different pH and ionic compositions, eg, normal saline, non‐diluted seawater and diluted seawater, on nasal mucosa functional parameters.

Methods

For this randomized, controlled, blinded, in vitro study, we used airway epithelial cells obtained from 13 nasal polyps explants to measure ciliary beat frequency (CBF) and epithelial wound repair speed (WRS) in response to 3 isotonic nasal irrigation solutions: (1) normal saline 0.9%; (2) non‐diluted seawater (Physiomer®); and (3) 30% diluted seawater (Stérimar). The results were compared to control (cell culture medium).

Results

Non‐diluted seawater enhanced the CBF and the WRS when compared to diluted seawater and to normal saline. When compared to the control, it significantly enhanced CBF and slightly, though nonsignificantly, improved the WRS. Interestingly, normal saline markedly reduced the number of epithelial cells and ciliated cells when compared to the control condition.

Conclusion

Our results suggest that the physicochemical features of the nasal wash solution is important because it determines the optimal conditions to enhance CBF and epithelial WRS thus preserving the respiratory mucosa in pathological conditions. Non‐diluted seawater obtains the best results on CBF and WRS vs normal saline showing a deleterious effect on epithelial cell function.

Clinical effects of topical antifungal therapy in chronic rhinosinusitis: a randomized, double-blind, placebo-controlled trial of intranasal fluconazole

Several studies have been in favor of fungi as a possible pathogenesis of chronic rhinosinusitis (CRS); however, to date, there is no scientific consensus about the use of antifungal agents in disease management. The aim of the present study was to investigate the efficacy of intranasal fluconazole in improving disease symptoms and objective outcomes of patients with CRS. A randomized, double-blind, placebo-controlled study was conducted on 54 patients who were diagnosed with CRS and had not been responsive to routine medical treatments. They were randomly assigned to receive either fluconazole nasal drop 0.2 % or placebo in addition to the standard regimen for a duration of 8 weeks. Patients' outcomes were evaluated according to Sino-Nasal Outcome Test 20 (SNOT-20), endoscopic scores, and Computed Tomography (CT) scores. No statistically significant difference was found in SNOT-20 (p = 0.201), endoscopic (p = 0.283), and CT scores (p = 0.212) of the patients at baseline and after 8-week course of treatment between drug and placebo group. Similar to many studies, the use of topical antifungal treatment for patients with CRS was not shown to be significantly effective. However, further studies are needed to obtain high levels of consistent evidence in order to arrive at a decision whether antifungal therapy is effective in management of CRS or not.

Impact of saline irrigation and topical corticosteroids on the postsurgical sinonasal microbiota

BACKGROUND

Topical treatments with nasal saline irrigation, topical steroid sprays, or corticosteroid rinses can improve sinonasal symptoms in chronic rhinosinusitis (CRS). However, the impact of these therapies on commensals (Corynebacterium) and on biofilm pathogens associated with CRS (Staphylococcus aureus and Pseudomonas) is not well characterized.

METHODS

Paired nasal and sinus swabs were collected endoscopically from 28 controls and 14 CRS patients with nasal polyposis (CRSwNP) who had not received systemic antibiotics or corticosteroids in the previous 8 weeks. Total DNA from swab eluents were extracted and analyzed by 16S rRNA gene-based pyrosequencing. A total of 359,077 reads were obtained and classified taxonomically. The association of use of topical therapies with sinonasal microbiota composition was assessed by factor/vector-fitting. The proportional abundances of sinonasal bacteria between topical therapy users and nonusers were further compared by 2-tailed Kolmogorov-Smirnov test among controls and among CRSwNP participants.

RESULTS

Nasal saline irrigation, with or without added budesonide, was not associated with significantly distinct sinonasal microbiota composition or significantly decreased Pseudomonas or S. aureus abundances among either controls or CRSwNP participants. Corynebacterium was slightly lower in controls that reported using saline irrigation than those who did not. No significant association was found between nasal saline irrigation and the proportional abundances of Pseudomonas, S. aureus, and Corynebacterium in CRSwNP participants. However, male CRSwNP patients were noted to have significantly higher Corynebacterium proportional abundances than their female counterparts. The use of topical steroid sprays was associated with a distinct microbiota in control subjects, characterized by higher proportional abundances of Dolosigranulum and Simonsiella and a lower proportional abundance of Campylobacter.

CONCLUSION

Nasal saline irrigation is not associated with a distinct alteration in the proportional abundance of commensal bacteria or biofilm-forming pathogens in CRSwNP patients. However, use of topical intranasal corticosteroid sprays in control subjects is associated with a distinct sinonasal microbiota.

The effectiveness topical amphotericin B in the management of chronic rhinosinusitis: a meta-analysis

Chronic rhinosinusitis (CRS) is believed to be the result of an exaggerated reaction to fungi in the nasal mucosa, and topical amphotericin B (AMB) is a commonly used treatment. The purpose of this study was to perform a meta-analysis of high-quality comparative studies to examine the efficacy of topical AMB for the treatment of CRS. A search was conducted of Medline, Cochrane, EMBASE, and ISI Web of Knowledge until December 31, 2013 using combinations of the search terms chronic rhinosinusitis, human, treatment, antibiotics, nasal irrigation, nebulized, nasal lavage, sinonasal rinses, and antimicrobials. Inclusion criteria were (1) comparative studies, (2) a diagnosis of CRS or chronic sinusitis, and (3) the intervention was a topical antifungal. The primary outcome measure was quality of life (QOL), and the secondary was nasal endoscopy score. Of 235 article initially identified, five randomized controlled trials were included in the meta-analysis. Analysis of four studies with complete QOL data found no difference between treatment and placebo groups [standard difference in means 0.78, 95 % confidence interval (CI) -0.25 to 1.81, P = 0.138]. Analysis of four studies with complete nasal endoscopy score data found no difference between the treatment and placebo groups (standard difference in means 0.34, 95 % CI -0.08 to 0.76, P = 0.117). AMB is not more effective than placebo in improving QOL or nasal endoscopy scores in patients with CRS.

Chronic cough: an update

Cough persisting beyond 8 weeks (ie, chronic cough) is one of the most common reasons for an outpatient visit. A protracted cough can negatively affect one's quality of life by causing anxiety, physical discomfort, social isolation, and personal embarrassment. Herein, the anatomy and physiology of the cough reflex are reviewed. Upper airway cough syndrome, asthma, eosinophilic bronchitis, and gastroesophageal reflux disease account for most chronic cough after excluding smoking, angiotensin-converting enzyme inhibitor use, and chronic bronchitis. Many patients have more than one reason for chronic cough. Treating the underlying cause(s) resolves cough in most instances. There are some coughs that seem refractory despite an extensive work-up. The possibility of a hypersensitive cough reflex response has been proposed to explain these cases. Several clinical algorithms to evaluate chronic cough are presented.