Allergic fungal sinusitis: pathophysiology, diagnosis and management

The molecular genetics of inflammatory, autoimmune, and infectious diseases of the sinonasal tract: a review

CONTEXT

The sinonasal tract is frequently affected by a variety of nonneoplastic inflammatory disease processes that are often multifactorial in their etiology but commonly have a molecular genetic component.

OBJECTIVE

To review the molecular genetics of a variety of nonneoplastic inflammatory diseases of the sinonasal tract.

DATA SOURCES

Inflammatory lesions of the sinonasal tract can be divided into 3 main categories: (1) chronic rhinosinusitis, (2) infectious diseases, and (3) autoimmune diseases/vasculitides. The molecular diagnosis and pathways of a variety of these inflammatory lesions are currently being elucidated and will shed light on disease pathogenesis and treatment.

CONCLUSIONS

The sinonasal tract is frequently affected by inflammatory lesions that arise through complex interactions of environmental, infectious, and genetic factors. Because these lesions are all inflammatory in nature, the molecular pathology surrounding them is most commonly due to upregulation and down-regulation of genes that affect inflammatory responses and immune regulation.

A five-year survey of dematiaceous fungi in a tropical hospital reveals potential opportunistic species

Dematiaceous fungi (black fungi) are a heterogeneous group of fungi present in diverse environments worldwide. Many species in this group are known to cause allergic reactions and potentially fatal diseases in humans and animals, especially in tropical and subtropical climates. This study represents the first survey of dematiaceous fungi in Malaysia and provides observations on their diversity as well as in vitro response to antifungal drugs. Seventy-five strains isolated from various clinical specimens were identified by morphology as well as an internal transcribed spacer (ITS)-based phylogenetic analysis. The combined molecular and conventional approach enabled the identification of three classes of the Ascomycota phylum and 16 genera, the most common being Cladosporium, Cochliobolus and Neoscytalidium. Several of the species identified have not been associated before with human infections. Among 8 antifungal agents tested, the azoles posaconazole (96%), voriconazole (90.7%), ketoconazole (86.7%) and itraconazole (85.3%) showed in vitro activity (MIC ≤1 µg/mL) to the largest number of strains, followed by anidulafungin (89.3%), caspofungin (74.7%) and amphotericin B (70.7%). Fluconazole appeared to be the least effective with only 10.7% of isolates showing in vitro susceptibility. Overall, almost half (45.3%) of the isolates showed reduced susceptibility (MIC >1 µg/mL) to at least one antifungal agent, and three strains (one Pyrenochaeta unguis-hominis and two Nigrospora oryzae) showed potential multidrug resistance.

Fungal allergy in asthma-state of the art and research needs

Sensitization to fungi and long term or uncontrolled fungal infection are associated with poor control of asthma, the likelihood of more severe disease and complications such as bronchiectasis and chronic pulmonary aspergillosis. Modelling suggests that >6.5 million people have severe asthma with fungal sensitizations (SAFS), up to 50% of adult asthmatics attending secondary care have fungal sensitization, and an estimated 4.8 million adults have allergic bronchopulmonary aspergillosis (ABPA). There is much uncertainty about which fungi and fungal allergens are relevant to asthma, the natural history of sensitisation to fungi, if there is an exposure response relationship for fungal allergy, and the pathogenesis and frequency of exacerbations and complications. Genetic associations have been described but only weakly linked to phenotypes. The evidence base for most management strategies in ABPA, SAFS and related conditions is weak. Yet straightforward clinical practice guidelines for management are required. The role of environmental monitoring and optimal means of controlling disease to prevent disability and complications are not yet clear. In this paper we set out the key evidence supporting the role of fungal exposure, sensitisation and infection in asthmatics, what is understood about pathogenesis and natural history and identify the numerous areas for research studies.

Allergic sensitization in Canadian chronic rhinosinusitis patients

BACKGROUND

Chronic rhinosinusitis (CRS) is a societal burden and cause of morbidity in Canada; however, the prevalence of allergic sensitization in Canadian CRS patients has remained poorly characterized.

OBJECTIVE

In this study, we used skin prick test (SPT) and specific immunoglobulin E (sIgE) and G (sIgG) titers to regionally relevant allergen sources in order to determine whether allergic sensitization is more prevalent in CRS patients compared to chronic idiopathic urticaria (CIU) control patients.

METHODS

One hundred and fifty eight subjects (19-70 years of age) were recruited into the study. 101 subjects had a confirmed diagnostic history of CRS and 57 subjects with a clinical diagnosis of CIU were recruited as controls. Enrolled subjects underwent SPT to a panel of perennial and seasonal allergens and sIgE titers were quantified to selected environmental allergen mixes (grass, mold, and tree species) using Phadia ImmunoCAP. sIgG was additionally quantified to Alternaria alternata, Aspergillus versicolor, Cladosporium herbarum, and Stachybotrys atra. Differences between CRS and control CIU patient SPT and serological data were examined by chi-squared analysis and analysis of variance.

RESULTS

Reactivity to at least one SPT extract occurred in 73% of CRS patients. Positive SPT reactivity to A. alternata (odds ratio (OR): 4.34, 95% confidence interval: 1.57, 12.02), cat (OR: 3.23, 95% CI: 1.16, 9.02), and ragweed (OR: 2.31, 95% CI: 1.02, 5.19) extracts were more prevalent in patients with CRS (p < 0.05). Although dust mite and timothy grass sensitization approached statistical significance in the chi-squared analysis of SPT data, other common perennial and seasonal allergens were not associated with CRS. No statistically significant differences were observed between mean sIgE and sIgG titers in CRS and control patients.

CONCLUSIONS

This study supports previous data that suggests A. alternata sensitization is associated with CRS; however, these findings additionally highlight the contribution of other regionally important allergens including cat and ragweed.

Markers of disease severity and socioeconomic factors in allergic fungal rhinosinusitis

BACKGROUND

Allergic fungal rhinosinusitis (AFRS) is a refractory subtype of chronic rhinosinusitis. There is a paucity of data investigating the association of epidemiologic markers of disease severity. The primary objective of this study is to evaluate components of disease severity with socioeconomic status and health care access.

METHODS

A retrospective analysis was performed on patients diagnosed with AFRS by Bent and Kuhn criteria from 2000 to 2013. Severity of disease was measured by orbitocranial involvement, bone erosion, Lund-Mackay score, serum immunoglobulin E (IgE), and mold hypersensitivity. The North Carolina State Data Center provided county-specific socioeconomic and demographic data. Fisher's exact test, Wilcoxon rank sum test, Pearson correlations, and multivariable linear regression models were used to explore associations between variables.

RESULTS

Of 93 patients, 58% were African American and 39% Caucasian with a male:female ratio of 1.4:1 and average age at presentation of 29 years. Race, age, insurance status, and gender were not associated with severity of disease. Bone erosion was correlated with residence in counties with lower income per capita (p = 0.01). Patients with orbitocranial involvement resided in more rural counties (p = 0.01) with less primary care providers per capita (p = 0.02). Residence in counties with older or poorer quality housing was associated with a higher prevalence of bone erosion (p = 0.02).

CONCLUSION

Within our cohort of patients residing in North Carolina, markers of disease severity (bone erosion and orbitocranial involvement) in AFRS were associated with lower income, rural counties, poor housing quality, and less health care access.

Sinus fungus ball in the Japanese population: clinical and imaging characteristics of 104 cases

Sinus fungus ball is defined as noninvasive chronic fungal rhinosinusitis occurring in immunocompetent patients with regional characteristics. The clinical and imaging characteristics of paranasal sinus fungus ball were retrospectively investigated in 104 Japanese patients. All patients underwent endoscopic sinus surgery. Preoperative computed tomography (CT), magnetic resonance (MR) imaging, age, sex, chief complaint, causative fungus, and clinical outcome were analyzed. Patients were aged from 25 to 79 years (mean 58.8 years). Female predominance was noted (58.7%). Most common symptoms were nasal discharge and facial pain. CT showed high density area in 82.0% of the cases (82/100), whereas T2-weighted MR imaging showed low intensity area in 100% of the cases (32/32). Histological examination showed that most causative agents were Aspergillus species (94.2% (98/104)). Culture test was positive for 16.7% (11/66). Recurrence was found in 3.2% (3/94). Older age and female predominance were consistent with previous reports. MR imaging is recommended to confirm the diagnosis.

Allergic fungal sinusitis and eosinophilic mucin rhinosinusitis: diagnostic criteria

BACKGROUND

Chronic sinusitis is one of the most common otolaryngological diagnoses. Allergic fungal sinusitis and eosinophilic mucin rhinosinusitis can easily be misdiagnosed and treated as chronic sinusitis, causing continuing harm.

AIM

To better identify and characterise these two subgroups of patients, who may suffer from a systemic disease requiring multidisciplinary treatment and prolonged follow up.

METHODS

A retrospective, longitudinal study of all patients diagnosed with allergic fungal sinusitis or eosinophilic mucin rhinosinusitis within one otolaryngology department over a 15-year period.

RESULTS

Thirty-four patients were identified, 26 with eosinophilic mucin rhinosinusitis and 8 with allergic fungal sinusitis. Orbital involvement at diagnosis was commoner in allergic fungal sinusitis patients (50 per cent) than eosinophilic mucin rhinosinusitis patients (7.7 per cent; p < 0.05). Asthma was diagnosed in 73 per cent of eosinophilic mucin rhinosinusitis patients and 37 per cent of allergic fungal sinusitis patients.

CONCLUSION

Allergic fungal sinusitis and eosinophilic mucin rhinosinusitis have the same clinical presentation but different clinical courses. The role of fungus and the ability to confirm its presence are still problematic issues, and additional studies are required.

Airway and parenchymal manifestations of pulmonary aspergillosis

Pulmonary aspergillosis encompasses a heterogeneous group of mycoses that result from either colonisation or pathogenic damage of lung tissue by Aspergillus fungi. These clinical entities range from relatively benign saprophytic hypersensitivity associated with fungal inhabitation to life threatening invasive disease. The diagnosis of pulmonary disorders related to Aspergillus is on the increase and it is more important than ever those both general and respiratory physicians have a good understanding of these disorders. This paper reviews the contemporary understanding of the clinical, radiographic and histopathological aspects of pulmonary aspergillosis.

The role of fungi in diseases of the nose and sinuses

BACKGROUND

Human exposure to fungal elements is inevitable, with normal respiration routinely depositing fungal hyphae within the nose and paranasal sinuses. Fungal species can cause sinonasal disease, with clinical outcomes ranging from mild symptoms to intracranial invasion and death. There has been much debate regarding the precise role fungal species play in sinonasal disease and optimal treatment strategies.

METHODS

A literature review of fungal diseases of the nose and sinuses was conducted.

RESULTS

Presentation, diagnosis, and current management strategies of each recognized form of fungal rhinosinusitis was reviewed.

CONCLUSION

Each form of fungal rhinosinusitis has a characteristic presentation and clinical course, with the immune status of the host playing a critical pathophysiological role. Accurate diagnosis and targeted treatment strategies are necessary to achieve optimal outcomes.

Role of fungi in the pathophysiology of chronic rhinosinusitis: an update

The pathogenesis of chronic rhinosinusitis (CRS) is multi-factorial with an infectious process likely at least partly involved. While bacteria have been proposed to play a critical role in CRS, fungi have also been implicated by some investigators, although the pathogenesis of fungi in CRS represents a significant controversy among rhinologists. Fungal-associated factors believed to be involved in CRS include the ability of fungi to induce significant inflammatory reactions by different means through inducing localized cytokine production in the sinonasal tract. Despite these observations, randomized, controlled studies on CRS patients using antifungal therapy have not resulted in significant improvement in CRS patients. The role of fungi in the pathogenesis of CRS remains controversial.

Fungal disease of the nose and sinuses: an updated overview

Fungal diseases of the nose and sinuses encompasses a diverse spectrum of disease. Clinical manifestations are largely dependent upon the immune status of the host, as, given the ubiquitous nature of these organisms, exposure is unavoidable. Asymptomatic colonization of the nasal passages by fungi warrants no treatment and is common, while allergic fungal rhinosinusitis is challenging and often requires a combined approach of surgical intervention, immunotherapy, and corticosteroid administration. A diagnosis requires a combination of IgE immune reactivity, eosinophilic infiltration, and fungi recovery. Similarly, invasive disease may present only after several months of slowly progressive disease, or in rapid and fulminant fashion in the appropriate host. A differentiation of these overlapping syndromes and the pathophysiologic processes at play, and recommended treatment algorithms, are the focus of this review.

Immunotherapy for allergic fungal sinusitis

PURPOSE OF REVIEW

Allergic fungal sinusitis (AFS) results from an immunoglobulin E (IgE)-mediated, eosinophil-predominant hypersensitivity reaction to extramucosal fungi within the paranasal sinuses. Although the pathogenesis of this noninvasive process is still not fully understood, there is new information. Recently, the use of allergen immunotherapy with fungal antigens as an adjunct in treatment of AFS has been evaluated. In this review, we summarize the experience in the published literature on the topic.

RECENT FINDINGS

There is evidence to suggest that allergen immunotherapy to fungal allergens may be effective in the treatment of symptoms of AFS and may decrease the rate of postoperative exacerbations and further operations. There is no evidence that this therapy induces immune complex disease. These studies pave the way for controlled trials of immunotherapy in patients with AFS.

SUMMARY

Allergen immunotherapy to fungi shows promise as a treatment to decrease the recurrence of AFS and should be considered a part of the treatment regimen. However, because the number of patients treated has been small and one study suggested that fungal immunotherapy administered before removal of fungal contents from the sinuses could worsen sinusitis, controlled studies are essential to moving forward.

Invasive maxillary aspergillosis masquerading as malignancy in two cases: Utility of cytology as a rapid diagnostic tool

Fungi have emerged as important etiological agents for chronic sinusitis. Invasive aspergillosis has been reported in immunocompromised individuals or diabetics; however, it is uncommonly seen in immunocompetent patients. Definitive diagnosis of these lesions is based on histological examination and fungal culture. We report two cases of invasive maxillary lesions in immunocompetent patients, clinically suspected of malignancy; however, fine needle aspiration cytology showed fungal hyphae, morphologically suggestive of Aspergillus, which was later confirmed on histopathology. Aspiration cytology thus plays a crucial role in the early and definitive diagnosis of fungal sinusitis in cases clinico-radiologically suspected of malignancy. An early diagnosis will help the clinician for early and appropriate management and follow-up in order to decrease the high morbidity and mortality associated with it.

The presence of fungal floras in sinuses in chronic sinusitis patients with polyps

Several fungal species are known to cause severe respiratory and cutaneous diseases. The aim of this work was to analyze the fungal flora in maxillary sinuses in patients suffering from chronic sinusitis with polyps. Twenty five patients (11 woman, 14 man) who underwent endoscopic surgical procedures were included into the study. During the operation, the smear from the maxillary sinus were obtained for the incubation. In 6 persons fungal floras was present.

Fungal rhinosinusitis: a retrospective microbiologic and pathologic review of 400 patients at a single university medical center

Fungal Rhinosinusitis (FRS) is a well known entity, but only in more recent times have the types of FRS been more fully defined. In this study, we evaluate the diagnosis of FRS in a single medical center. Cases were divided into 2 main categories, non-invasive and invasive. Non-invasive FRS included fungus ball (FB) and allergic fungal rhinosinusitis (AFRS). Invasive FRS included acute invasive fungal rhinosinusitis (AIFRS), chronic invasive fungal rhinosinusitis (CIFRS), and chronic invasive granulomatous fungal rhinosinusitis (CGFRS). Fungal culture data, if available was reviewed. 400 patients with FRS were identified. 87.25% were non-invasive (45% AFRS, 40% FB, and 2% combined AFRS and FB and 12.5% were invasive 11% AIFRS 1.2% CIFRS 0.5% CGFRS. One patient (0.25%) had combined FB/CGFRS. Aspergillus sp. or dematiaceous species were the most common fungi isolated in AFS while Aspergillus sp. was most common in FB and AIFRS. In our experience, most FRS is non-invasive. In our patient population, invasive FRS is rare with AIFRS representing >90% of cases. Culture data supports that a variety of fungal agents are responsible for FRS, but Aspergillus sp. appears to be one of the most common organisms in patients with FRS.

Fungi linking the pathophysiology of chronic rhinosinusitis with nasal polyps and allergic asthma

The immunologic reaction to fungal stimuli has long been thought to be a contributor to the development of sinonasal disease. We aim to review the role of fungi in upper and lower airway inflammatory diseases. The immune response to fungi in the pathogenicity of specific respiratory inflammatory diseases such as allergic bronchopulmonary aspergillosis and a subtype of CRS known as allergic fungal rhinosinusitis has been relatively well described. Fungi are thought to serve both as immunogenic antigens and as adjuncts to inflammation through protease activity. Development of a recent murine mouse model of asthma bypassing the pre-sensitization of allergen further suggests a broader role for fungi in allergic asthma. The literature is lacking in defining a clear presence of fungi within the inflamed sinus cavity of CRS patients and its potential immunologic effects, as well as the utility of antifungal therapy for CRS management. We will review these data and potential common molecular mechanisms activated by fungi in the common pathway toward upper and lower airway inflammatory pathology.

Fungal disease of the nose and paranasal sinuses

Fungal infections of the nose and paranasal sinuses represent a spectrum of diseases ranging from colonization to invasive rhinosinusitis. Clinical manifestations are largely dependent on the immune status of the host, and given the ubiquitous nature of these organisms, exposure is unavoidable. Noninvasive disease includes asymptomatic fungal colonization, fungus balls, and allergic fungal rhinosinusitis. Invasive disease includes indolent chronic rhinosinusitis, granulomatous fungal sinusitis, and acute fulminant fungal rhinosinusitis. A differentiation of these somewhat overlapping syndromes and the disparate treatment regimens required for effective management are the focus of this review.

Pro-inflammatory effects of ochratoxin A on nasal epithelial cells

Eosinophilic chronic rhinosinusitis (ECRS) largely consists of allergic fungal sinusitis, non-allergic fungal rhinosinusitis, aspirin-exacerbated ECRS, and superantigen-induced ECRS. The pathophysiology of ECRS is not completely understood, in particular, the role of mycotoxins remains unknown. The aim of this study was to evaluate the effects of one of the most widespread mycotoxin, ochratoxin A (OTA), on the release of pro-inflammatory cytokines such as interleukin-(IL)-6 and the CXC-chemokine IL-8 from nasal epithelial cell cultures (NEC) of subjects with and without ECRS. NEC (ECRS group: n = 16; controls: n = 7) were stimulated with OTA for 24 h. Protein concentrations of IL-6 and IL-8 levels were measured in NEC supernatants by ELISA prior and 24 h after addition of OTA. Baseline levels in the supernatants of NEC were 183.3 pg/ml for IL-6 and 384.6 pg/ml for IL-8. Stimulation with OTA induced a significant increase of IL-6 (p < 0.001) and IL-8 (p < 0.001) in both NEC of controls and ECRS, respectively. There were no significant differences between controls and ECRS. This is the first study evaluating the effects of a mycotoxin on epithelial airway cells. Our data show that the ubiquitous mycotoxin OTA has a strong pro-inflammatory effect on NEC resulting in the release of IL-6 and IL-8. Mycotoxins may promote inflammation in nasal mucosa.

The Role of Antifungal Therapy in the Prevention of Recurrent Allergic Fungal Rhinosinusitis after Functional Endoscopic Sinus Surgery: A Randomized, Controlled Study

Allergic fungal rhinosinusitis (AFRS) is the most common form of fungal sinus disease. Its recurrence rate is high despite numerous strategies to prevent it. We conducted a study to assess the effect of systemic and topical antifungal agents—both separately and in combination—in preventing recurrence of AFRS following functional endoscopic sinus surgery (FESS). Our initial study population was made up of 50 adults who were diagnosed with AFRS by clinical, radiologic, histopathologic, and laboratory workup and who subsequently underwent FESS. Postoperatively, these patients were randomized into 5 different treatment groups matched for sex, age, and socioeconomic status. Four of the groups received a different antifungal regimen in addition to convenient medical treatment (CMT), while a fifth group served as a control. The antifungal regimens included oral itraconazole (group A), fluconazole nasal spray (group B), combined oral itraconazole and nasal fluconazole (group C), and irrigation with a fluconazole solution through the nasal fossa (group D); the group of 10 controls (group E) received CMT only. A total of 41 patients were available for follow-up (9 mo maximum). Recurrence rates in the 5 groups were 66.7, 10.0, 14.3, 28.6, and 75.0%, respectively. Based on our findings, we conclude that treatment with topical fluconazole as either a nasal spray or an irrigation solution can significantly reduce the rate of recurrence of AFRS after FESS.

Histopathologic diagnosis of fungal infections in the 21st century

Fungal infections are becoming more frequent because of expansion of at-risk populations and the use of treatment modalities that permit longer survival of these patients. Because histopathologic examination of tissues detects fungal invasion of tissues and vessels as well as the host reaction to the fungus, it is and will remain an important tool to define the diagnostic significance of positive culture isolates or results from PCR testing. However, there are very few instances where the morphological characteristics of fungi are specific. Therefore, histopathologic diagnosis should be primarily descriptive of the fungus and should include the presence or absence of tissue invasion and the host reaction to the infection. The pathology report should also include a comment stating the most frequent fungi associated with that morphology as well as other possible fungi and parasites that should be considered in the differential diagnosis. Alternate techniques have been used to determine the specific agent present in the histopathologic specimen, including immunohistochemistry, in situ hybridization, and PCR. In addition, techniques such as laser microdissection will be useful to detect the now more frequently recognized dual fungal infections and the local environment in which this phenomenon occurs.

Melanized fungi in human disease

Melanized or dematiaceous fungi are associated with a wide variety of infectious syndromes, including chromoblastomycosis, mycetoma, and phaeohyphomycosis. [corrected]. Many are soil organisms and are generally distributed worldwide, though certain species appear to have restricted geographic ranges. Though they are uncommon causes of disease, melanized fungi have been increasingly recognized as important pathogens, with most reports occurring in the past 20 years. The spectrum of diseases with which they are associated has also broadened and includes allergic disease, superficial and deep local infections, pneumonia, brain abscess, and disseminated infection. For some infections in immunocompetent individuals, such as allergic fungal sinusitis and brain abscess, they are among the most common etiologic fungi. Melanin is a likely virulence factor for these fungi. Diagnosis relies on careful microscopic and pathological examination, as well as clinical assessment of the patient, as these fungi are often considered contaminants. Therapy varies depending upon the clinical syndrome. Local infection may be cured with excision alone, while systemic disease is often refractory to therapy. Triazoles such as voriconazole, posaconazole, and itraconazole have the most consistent in vitro activity. Further studies are needed to better understand the pathogenesis and optimal treatment of these uncommon infections.

Inflammatory diseases of the nasal cavities and paranasal sinuses

Inflammatory diseases of the nose and paranasal sinus are commonly encountered in diagnostic histopathology. This review describes the possible manifestations of the common diseases as well as highlighting some of the uncommon causes of sinonasal inflammation which may have importance for treatment and prognosis. The diagnosis of fungal sinusitis is primarily histological. It is important to distinguish between invasive and non-invasive fungal sinusitis, the latter including allergic fungal sinusitis characterized by 'allergic mucin' and scanty fungal hyphae. Nasal eosinophilia is a feature of both allergic and non-allergic rhinosinusitis and a wide range of secondary changes in inflammatory polyps may lead to diagnostic confusion. Nasal biopsies are often taken from perforations or inflammatory masses to confirm or exclude granulomatous diseases. There is a broad differential diagnosis for granulomatous sinonasal disease and pathologists should appreciate the diagnostic histological and clinical features of these conditions.