Effects of long-term clarithromycin treatment on lavage-fluid markers of inflammation in chronic rhinosinusitis

Immunomodulatory Effects of Macrolides Considering Evidence from Human and Veterinary Medicine

Macrolide antimicrobial agents have been in clinical use for more than 60 years in both human and veterinary medicine. The discovery of the non-antimicrobial properties of macrolides and the effect of immunomodulation of the inflammatory response has benefited patients with chronic airway diseases and impacted morbidity and mortality. This review examines the evidence of antimicrobial and non-antimicrobial properties of macrolides in human and veterinary medicine with a focus toward veterinary macrolides but including important and relevant evidence from the human literature. The complete story for these complex and important molecules is continuing to be written.

Alantolactone Enhances the Phagocytic Properties of Human Macrophages and Modulates Their Proinflammatory Functions

Aim of the Study

Phagocytosis is a crucial element of innate immune defense involved in bacterial killing. The aim of our study was to evaluate the influence of alantolactone on phagocytosis and cytokines release by THP1-derived macrophages. We assessed whether antimicrobial compound alantolactone (a sesquiterpene lactone present in Inula helenium L.) is able to stimulate immune functions of macrophages by increase of S. aureus uptake, phagosome acidification and further stimulation of phago-lysosomes formation. Simultaneously, we tested influence of alantolactone on cytokines/chemokines production and p65 NF-κB concentration. The activity of alantolactone was compared with clarithromycin at concentration 20 µM.

Methods

The cytotoxicity of alantolactone as well as S. aureus uptake, pH of phagosomes and phago-lysosomes fusion were analysed with flow cytometry. Reactive oxygen species and superoxide production were evaluated spectrophotometrically. The efficiency of phagocytosis was evaluated via quantifying viable bacteria (CFU). The effect on p65 protein concentration and cytokine production by macrophages were measured by enzyme-linked immunosorbent assay (ELISA).

Results

Alantolactone enhanced phagocytosis via increase of S. aureus uptake, acidification of phagosomes, and later stimulation of phago-lysosomes fusion. Alantolactone treatment resulted in ROS and superoxide production decrease. Furthermore, alantolactone inhibited production of pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and IL-8 as well as decreased p65 concentration, the subunit responsible for NF-κB activation and cytokine production and simultaneously stimulated release of anti-inflammatory mediators (IL-10 and TGF-β).

Conclusion

Results of our study indicate that alantolactone enhances clearance of S. aureus, and simultaneously modulates immune response, preventing collateral damage of the surrounding tissues. Considering the importance of phagocytosis in the pathogen killing, alantolactone may have a great potential as the supportive treatment of S. aureus infections. Further in vivo studies are warranted to confirm this hypothesis.

Inula helenium and Grindelia squarrosa as a source of compounds with anti-inflammatory activity in human neutrophils and cultured human respiratory epithelium

ETHNOPHARMACOLOGICAL RELEVANCE

During the epidemic season, over 90% of acute wheezing disease is associated with bronchial inflammation. Both neutrophil- and eosinophil-mediated inflammation have been involved in the pathophysiology of acute bronchitis, but neutrophil cell recruitment has been shown to be dominant. The ongoing inflammation increases the chemotaxis of neutrophils to inflamed site providing to their overaccumulation. The pharmacological reduction of neutrophil migration can be limited by suppression of major chemo-attractants and cytokines (IL-8, IL-1β and TNF-α) release and downregulation of adhesive molecules.

AIM OF THE STUDY

During a screening of plants traditionally used in respiratory tracts diseases (e.g. cough, rhinitis, bronchitis, throat infection, fever, influenza) in Europe, we have selected roots of Inula helenium and aerial parts of Grindelia squarrosa as a potential source of compounds limiting neutrophil migration.

MATERIALS AND METHODS

The effect on IL-8, IL-1β and TNF-α release by neutrophils and respiratory epithelium cell line (A549) was measured by enzyme-linked immunosorbent assay (ELISA). The surface expression of adhesive molecules was analyzed with flow cytometry, and the neutrophil attachment to the epithelial cells was assessed fluorimetrically.

RESULTS

We confirmed the ability of selected extracts and compounds to suppress neutrophil binding to the epithelium surface via downregulation of β2 integrin. Alantolactone and grindelic acid have shown significant suppression of IL-8, TNF-α and IL-1β release comparable with budesonide, used as a positive control.

CONCLUSIONS

The present study demonstrated that Inula helenium and Grindelia squarrosa, which have been traditionally used in Europe as medicinal plants, are a valuable source of active compounds with anti-inflammatory activity. Our observations justify the traditional use of I. helenium and G. squarrosa for a treatment of inflammation-based diseases in respiratory tract.

In vitro activity and pharmacodynamic/pharmacokinetic parameters of clarithromycin and azithromycin: why they matter in the treatment of respiratory tract infections

Clarithromycin and azithromycin are second-generation macrolides established and widely used for treating a range of upper and lower respiratory tract infections. Extensive clinical trials data indicate that these drugs are highly effective in these applications and broadly comparable in their clinical and microbiological effectiveness. However, consideration of pharmacokinetic, metabolic, and tissue-penetration data, including the significant antibacterial activity of the metabolite 14-hydroxy-clarithromycin, plus the findings of pharmacodynamic modeling, provide evidence that the long half-life and lower potency of azithromycin predispose this agent to select for resistant isolates. Comparison of the “mutant-prevention concentrations” of clarithromycin and azithromycin, and examination of large-scale epidemiological data from Canada, also support the view that these drugs differ materially in their propensity to promote resistance among bacterial strains implicated in common respiratory infections, and that clarithromycin may offer important advantages over azithromycin that should be considered when choosing a macrolide to treat these conditions.

Eupatoriopicrin Inhibits Pro-inflammatory Functions of Neutrophils via Suppression of IL-8 and TNF-alpha Production and p38 and ERK 1/2 MAP Kinases

During chronic inflammation, neutrophils acting locally as effector cells not only activate antibacterial defense but also promote the inflammatory response. Interleukin 8 (IL-8), the main cytokine produced by activated neutrophils, positively correlates with the severity of respiratory tract diseases. By screening European plants traditionally used for treating respiratory tract diseases, we found that extracts of aerial parts of Eupatorium cannabinum inhibit IL-8 release from neutrophils. Using bioassay-guided fractionation, we identified five sesquiterpene lactones, eupatoriopicrin (1), 5'-deoxyeupatoriopicrin (2), hiyodorilactone A (3), 3-hydroxy-5'- O-acetyleupatoriopicrin = hiyodorilactone D (4), and hiyodorilactone B (5), that efficiently (IC₅₀ < 1 μM) inhibited IL-8 and TNF-α release in lipopolysaccharide (LPS)-stimulated human neutrophils. Moreover, all these sesquiterpene lactones suppressed the adhesion of human neutrophils to an endothelial monolayer by downregulating the expression of the β2 integrin CD11b/CD18 on the neutrophil surface. Furthermore, eupatoriopicrin efficiently suppressed LPS-induced phosphorylation of p38 MAPK and ERK and attenuated neutrophil infiltration in the thioglycolate-induced peritonitis model in mice. Altogether, these results demonstrate the potential of the sesquiterpene lactone eupatoriopicrin as a lead substance for targeting inflammation.

Effects of Phytochemically Characterized Extracts From Syringa vulgaris and Isolated Secoiridoids on Mediators of Inflammation in a Human Neutrophil Model

Aim of the study: The aim of the present study was to investigate the effects of phytochemically characterized extracts connected with the traditional use (infusions and ethanolic extracts) of different parts of Syringa vulgaris (common lilac) on the pro-inflammatory functions of neutrophils. Active compounds were isolated from the most promising extract(s) using bioassay-guided fractionation, and their activity and molecular mechanisms of action were determined.

Methods: The extracts were characterized using a HPLC-DAD- MSⁿ method. The effects on ROS, MMP-9, TNF-α, IL-8, and MCP-1 production by neutrophils were measured using luminol-dependent chemiluminescence and enzyme-linked immunosorbent assay (ELISA) methods. The effects on p38MAPK, ERK1/2, JNK phosphorylation, and NF-kB p65 translocation were determined using western blots.

Results: The major compounds detected in the extracts and infusions belong to structural groups, including caffeic acid derivatives, flavonoids, and iridoids. All extracts and infusions were able to significantly reduce ROS and IL-8 production. Bioassay-guided fractionation led to the isolation of the following secoiridoids: 2″-epiframeroside, oleonuezhenide, oleuropein, ligstroside, neooleuropein, hydroxyframoside, and framoside. Neooleuropein appeared to be the most active compound in the inhibition of cytokine production by attenuating the MAP kinase pathways.

Conclusion: The present study demonstrated that common lilac, which is a traditionally used medicinal plant in Europe, is a valuable source of active compounds, especially neooleuropein.

The Immunomodulatory Effects of Macrolides-A Systematic Review of the Underlying Mechanisms

Background

The mechanisms underlying the non-antimicrobial immunomodulatory properties of macrolides are not well understood.

Objectives

To systematically review the evidence for the immunomodulatory properties of macrolides in humans and to describe the underlying mechanism and extent of their influence on the innate and adaptive immune system.

Methods

A systematic literature search was done in MEDLINE using the OVID interface from 1946 to December 2016 according to the preferred reporting items for systematic reviews and meta-analysis (PRISMA). Original articles investigating the influence of four macrolides (azithromycin, clarithromycin, erythromycin, and roxithromycin) on immunological markers in humans were included.

Results

We identified 22 randomized, controlled trials, 16 prospective cohort studies, and 8 case–control studies investigating 47 different immunological markers (186 measurements) in 1,834 participants. The most frequently reported outcomes were a decrease in the number of neutrophils, and the concentrations of neutrophil elastase, interleukin (IL)-8, IL-6, IL-1beta, tumor necrosis factor (TNF)-alpha, eosinophilic cationic protein, and matrix metalloproteinase 9. Inhibition of neutrophil function was reported more frequently than eosinophil function. A decrease in T helper (Th) 2 cells cytokines (IL-4, IL-5, IL-6) was reported more frequently than a decrease in Th1 cytokines (IL-2, INF-gamma).

Conclusion

Macrolides influence a broad range of immunological mechanisms resulting in immunomodulatory effects. To optimize the treatment of chronic inflammatory diseases by macrolides, further studies are necessary, particularly comparing different macrolides and dose effect relationships.

Clarithromycin in the Management of Chronic Rhinosinusitis: Preliminary Results of a Possible Its New Use

The aim of this study is to evaluate the efficacy and safety of prolonged therapy with low-dose clarithromycin in patients with chronic rhinosinusitis with polyps (CRSwP) after endoscopic sinus surgery (ESS). A total of 10 patients with CRSwP were identified and subjected to bilateral ESS. In post-operative patients they were treated with nasal wash with saline solution and steroid sprays (beclomethasone). During follow-up, after 30-40 days after the operation (M = 35.4 SD = +4.33), patients reported a worsening of symptoms with onset of nasal obstruction; reduction/loss of smell; headache; onset of viscous secretions and therefore all patients continued therapy with saline nasal irrigation, topical steroid therapy and started macrolide (clarithromycin 500 mg/pill: 1 pill/day for 3 days a week for 1 month). 22-item SinoNasal Outcome Test (SNOT-22) and a score to the endoscopic evaluation (endoscopic appearance score, EAS) before and after treatment were performed to evaluate efficacy of treatment. The results of the SNOT-22 and EAS showed statistically significant improvements (p < 0.05) for some parameters such as: the need to blow nose, sneezing, hyposmia, viscous mucous secretions about the SNOT-22 and reduction of secretions and edema of the nasal mucosa about the EAS. The preliminary results of our study show that the low-dose clarithromycin for a period of 1 month can improve patient complaints with CRSwP not only through the antibacterial properties but also for the immunomodulatory characteristics.

Clarithromycin and dexamethasone show similar anti-inflammatory effects on distinct phenotypic chronic rhinosinusitis: an explant model study

BACKGROUND

Phenotype of chronic rhinosinusitis (CRS) may be an important determining factor of the efficacy of anti-inflammatory treatments. Although both glucocorticoids and macrolide antibiotics have been recommended for the treatment of CRS, whether they have different anti-inflammatory functions for distinct phenotypic CRS has not been completely understood. The aim of this study is to compare the anti-inflammatory effects of clarithromycin and dexamethasone on sinonasal mucosal explants from different phenotypic CRS ex vivo.

METHODS

Ethmoid mucosal tissues from CRSsNP patients (n = 15), and polyp tissues from eosinophilic (n = 13) and non-eosinophilic (n = 12) CRSwNP patients were cultured in an ex vivo explant model with or without dexamethasone or clarithromycin treatment for 24 h. After culture, the production and/or expression of anti-inflammatory molecules, epithelial-derived cytokines, pro-inflammatory cytokines, T helper (Th)1, Th2 and Th17 cytokines, chemokines, dendritic cell relevant markers, pattern recognition receptors (PRRs), and tissue remodeling factors were detected in tissue explants or culture supernatants by RT-PCR or ELISA, respectively.

RESULTS

We found that both clarithromycin and dexamethasone up-regulated the production of anti-inflammatory mediators (Clara cell 10-kDa protein and interleukin (IL)-10), whereas down-regulated the production of Th2 response and eosinophilia promoting molecules (thymic stromal lymphopoietin, IL-25, IL-33, CD80, CD86, OX40 ligand, programmed cell death ligand 1, CCL17, CCL22, CCL11, CCL5, IL-5, IL-13, and eosinophilic cationic protein) and Th1 response and neutrophilia promoting molecules (CXCL8, CXCL5, CXCL10, CXCL9, interferon-γ, and IL-12), from sinonasal mucosa from distinct phenotypic CRS. In contrast, they had no effect on IL-17A production. The expression of PRRs (Toll-like receptors and melanoma differentiation-associated gene 5) was induced, and the production of tissue remodeling factors (transforming growth factor-β1, epidermal growth factor, basic fibroblast growth factor, platelet derived growth factor, vascular endothelial growth factor, and matrix metalloproteinase 9) was suppressed, in different phenotypic CRS by dexamethasone and clarithromycin in comparable extent.

CONCLUSIONS

Out of our expectation, our explant model study discovered herein that glucocorticoids and macrolides likely exerted similar regulatory actions on CRS and most of their effects did not vary by the phenotypes of CRS.

High and low doses of clarithromycin treatment are associated with different clinical efficacies and immunomodulatory properties in chronic rhinosinusitis

BACKGROUND

Low-dose clarithromycin has been recommended for the treatment of chronic rhinosinusitis without nasal polyps. However, it is uncertain whether a high dose of clarithromycin is more effective than a low dose.

METHODS

Forty-three chronic rhinosinusitis patients were randomised to low-dose or high-dose clarithromycin groups, and clinical efficacy was evaluated. Pre- and post-treatment measures included: nasal symptom assessment, endoscopic inspection (Lund-Kennedy system), a quality of life questionnaire (the Sino-Nasal Outcome Test 20) and examination of cytokine levels (interleukin-5 and -8) in nasal secretions.

RESULTS

The high dose of clarithromycin was significantly better in terms of clinical efficacy than the low dose for the treatment of chronic rhinosinusitis (p < 0.025). Significant differences in nasal cytokine levels (interleukin-5 and -8) were also observed between the low-dose and high-dose groups after short-term clarithromycin treatment (p < 0.025).

CONCLUSION

Short-term, high-dose clarithromycin appears to be more effective for the treatment of chronic rhinosinusitis than low-dose clarithromycin.

What is the proper role of oral antibiotics in the treatment of patients with chronic sinusitis?

PURPOSE OF REVIEW

Chronic rhinosinusitis is a common illness for which systemic antibiotics are frequently prescribed, although high-level evidence for this practice is largely lacking. We review the available literature addressing the proper role of oral antibiotics in the treatment of chronic rhinosinusitis.

RECENT FINDINGS

Chronic rhinosinusitis is an incompletely understood disease process for which the role of antibiotics remains difficult to define despite its historical prominence. There is no high-level evidence to support the use of oral antibiotics in chronic rhinosinusitis. Placebo-controlled studies of macrolide antibiotics indicate either no effect or limited degrees of improvement. Recent literature has identified that sinusitis refractory to medical therapy may represent an odontogenic source, and this should be addressed by dental surgery rather than by additional antibiotics.

SUMMARY

Oral antibiotics can be prescribed most confidently for the management of chronic rhinosinusitis when purulent exacerbations of disease are detected endoscopically and antibiotic choices are directed by culture. Long-term macrolide antibiotic therapy, acting through immunomodulatory pathways, may be of benefit in chronic rhinosinusitis patients with low immmunoglobulin E levels. Odontogenic sources of sinusitis are best detected by a computed tomography scan and treated through dental surgery. There is no high-level experimental evidence to support the use of oral antibiotics in the management of chronic rhinosinusitis. The challenge continues to be the inability to perform double-blinded studies, as both patients and physicians are generally unwilling to participate in chronic sinusitis treatment studies with a placebo arm, given the deep-seated belief of oral antibiotic efficacy in treatment.

Effect of long-term, low-dose clarithromycin on T helper 2 cytokines, eosinophilic cationic protein and the 'regulated on activation, normal T cell expressed and secreted' chemokine in the nasal secretions of patients with nasal polyposis

BACKGROUND

Little is known about the effects of macrolides on the cytokines and chemokines that modulate the function of eosinophils in nasal polyposis.

METHODS

Twenty-two non-allergic and 18 allergic patients with nasal polyps were administered clarithromycin 500 mg/day (single oral dose) for eight weeks. We measured the nasal secretion levels of the T helper 2 (also known as Th2) cytokines interleukin 4, 5 and 6, the 'regulated on activation, normal T cell expressed and secreted' (also known as RANTES) chemokine, and the eosinophilic cationic protein, before and after treatment.

RESULTS

After clarithromycin treatment, we found reduced levels of the 'regulated on activation, normal T cell expressed and secreted' chemokine in samples from both non-allergic and allergic patients (p < 0.05). Clarithromycin treatment decreased the levels of eosinophilic cationic protein only in non-allergic patients (p < 0.05), and decreased the level of interleukin 6 only in allergic patients (p < 0.05). Decreased levels of the 'regulated on activation, normal T cell expressed and secreted' chemokine were associated with a reduction in polyp size both in non-allergic and allergic patients.

CONCLUSION

Clarithromycin has a strong anti-inflammatory effect in nasal polyposis, but has different immunomodulatory effects in allergic and non-allergic nasal polyposis patients.

Antimicrobials and chronic rhinosinusitis with or without polyposis in adults: an evidenced-based review with recommendations

BACKGROUND

Chronic rhinosinusitis (CRS) is characterized by inflammation of the mucosa of the nose and paranasal sinuses. The role of bacterial or fungal infection in CRS is unclear, yet antimicrobials are commonly prescribed for this condition. Published guidelines offer little direction regarding antibiotic strategies for CRS. The purpose of this article is to provide an evidence-based approach to the use of antibacterial and antifungal antibiotics in the management of CRS.

METHODS

A systematic review of the literature was performed following recommendations of the Clinical Practice Guideline Manual, Conference on Guideline Standardization (COGS), and the Appraisal of Guidelines and Research Evaluation (AGREE). Inclusion criteria were: age ≥18 years old, chronic rhinosinusitis with or without polyps, antibiotic treatment as the experimental group, and clearly defined primary clinical endpoint. Studies involving patients with cystic fibrosis or acute invasive fungal sinusitis were excluded.

RESULTS

The review identified and evaluated the literature on 8 classes of antimicrobials for CRS: oral antibacterial antibiotics ≤3 weeks, oral antibacterial antibiotics >3 weeks, macrolide antibiotics, intravenous antibacterial antibiotics, topical antibacterial antibiotics, oral antifungals, intravenous antifungals, and topical antifungals.

CONCLUSION

Based on the available evidence, oral antibacterial antibiotics and prolonged macrolide antibiotics are considered therapeutic options in the treatment of CRS while the use of topical antibacterial antibiotics, intravenous antibacterial antibiotics and oral, topical, or intravenous antifungals would be recommended against. These evidence-based recommendations should not necessarily be applied to all patients with CRS and are not intended to supersede clinical judgment based on individual patient circumstances.

Comparison of efficacy of mometasone furoate versus clarithromycin in the treatment of chronic rhinosinusitis without nasal polyps in Chinese adults

BACKGROUND

Although both nasal steroids and macrolide antibiotics have been recommended for the treatment of chronic rhinosinusitis without nasal polyps (CRSsNPs), whether there is any difference in their clinical efficacy remains unexplored. In addition, few studies have investigated their clinical efficacy in a Chinese population living in China, who present distinct inflammatory patterns compared with white patients in western countries. This study compares the efficacy of mometasone furoate and clarithromycin treatment in CRSsNP in Chinese adults in a preliminary prospective, open-label, randomized trial.

METHODS

Forty-three CRSsNP patients were randomized to receive mometasone furoate nasal spray at 200 μg (n = 21) or clarithromycin tablet at 250 mg (n = 22) once daily for 12 weeks. Patients were assessed before the treatment and after 4, 8, and 12 weeks after treatment. Subjective symptoms were scored on a visual analog scale. Endoscopy physical findings were scored according to Lanza-Kennedy scoring system. Moreover, smoking and atopic status and coexistence of allergic rhinitis (AR) and asthma were recorded.

RESULTS

Before the treatment, no significant difference in symptoms and nasal endoscopic physical findings were found between mometasone furoate and clarithromycin group. As early as 4 weeks after dosing, a significant reduction of total symptom scores, nasal obstruction, headache, rhinorrhea and overall burden scores, and mucosal swelling and nasal discharge scores were observed in both groups. No significant difference in symptom or endoscopic scores was observed between these two groups at any posttreatment observation time point. The coexistence of AR was correlated with lower scores of mucosal edema and nasal secretion in the mometasone furoate group after 12-week treatment.

CONCLUSION

Mometasone furoate and clarithromycin show a comparable clinical effect for CRSsNPs in Chinese adults. Mometasone furoate is more effective in improving edema and secretion for CRSsNP patients with concomitant AR.

Chronic rhinosinusitis: therapeutic efficacy of anti-inflammatory and antibiotic approaches

Despite the high prevalence of chronic rhinosinusitis (CRS) worldwide, the exact pathogenesis of the disease remains unknown. Even with therapeutic intervention, treatment response is often only partial and frequently ineffective. The inability to define exact disease phenotypes in relation to specific disease mechanisms has led to a broad based approach with both anti-inflammatory and anti-microbial intervention. The clinical efficacy of such current therapeutic strategies is highlighted and the urgent need for further robust therapeutic intervention studies in CRS is discussed in this article.

Evaluation of long-term clarithromycin treatment in adult Chinese Patients with chronic rhinosinusitis without nasal polyps

OBJECTIVE

To evaluate the efficacy of long-term clarithromycin (CAM) treatment in adult Chinese patients suffering from chronic rhinosinusitis without nasal polyps (CRSnNP).

METHODS

Thirty-three CRSnNP patients were enrolled and subjected to CAM treatment for 12 weeks (250 mg daily). The total nasal symptom scores (TNSS), nasal resistance and inflammatory mediators including interleukin (IL)-8 and myeloperoxidase (MPO) were evaluated at weeks 0 and 12. Quality of life (QoL) was assessed in all patients by using the Sinonasal Outcome Test 20 and Short Form 36 questionnaires.

RESULTS

CAM treatment significantly improved TNSS, nasal resistance and QoL, and it inhibited IL-8 and MPO production in CRSnNP patients (p < 0.05). CAM treatment was more effective for IL-8(high) CRSnNP patients than for IL-8(low) CRSnNP patients (p < 0.05).

CONCLUSION

Long-term, low-dose CAM treatment is effective and safe for the treatment of CRSnNP in Chinese patients.

Maxillary sinus hypoplasia with a patent ostiomeatal complex: A therapeutic dilemma

OBJECTIVE

Maxillary sinus hypoplasia (MSH) is a radiologically detectable abnormality of the maxillary sinus that can be associated with sinusitis. Symptomatic MSH patients with a patent ostiomeatal complex (MSHPO) constitute a particular therapeutic challenge.

METHODS

Ostiomeatal unit CT scans of 1293 patients with various sinonasal symptoms such as purulent discharge, postnasal drip, facial pain or headache were reviewed to determine the incidence, clinical symptoms and outcomes of MSHPO following medical treatment.

RESULTS

Seventy-five cases (5.8%) were found to have MSHPO. Excluding patients with nasal septal deviation and positive allergy test, 37 of those 75 patients (2.86% of the original cohort) had MSHPO as the only definable sinonasal abnormality. Radiographs showed all patients had antral mucosal thickening. Postnasal drip (43.2%) was the most common symptom, followed by nasal obstruction (40.5%), purulent rhinorrhea (32.4%), hyposmia or anosmia (32.4%), cough (21.6%) and headache (18.9%). Medical treatment consisted of clarithromycin and ebastine for all patients. Medical treatment resulted in complete symptom resolution in only 24.3% of patients.

CONCLUSIONS

Primary MSHPO was present in approximately 3% of patients with sinonasal symptoms. The response rate to medical treatment was poor. MSHPO should be considered a differential diagnosis in patients presenting with non-specific sinonasal complaints.