Malignant otitis externa caused by Malassezia sympodialis

A Repertoire of the Less Common Clinical Yeasts

Invasive fungal diseases are a public health problem. They affect a constantly increasing number of at-risk patients, and their incidence has risen in recent years. These opportunistic infections are mainly due to Candida sp. but less common or rare yeast infections should not be underestimated. These so-called "less common" yeasts include Ascomycota of the genera Candida (excluding the five major Candida species), Magnusiomyces/Saprochaete, Malassezia, and Saccharomyces, and Basidiomycota of the genera Cryptococcus (excluding the Cryptococcus neoformans/gattii complex members), Rhodotorula, and Trichosporon. The aim of this review is to (i) inventory the less common yeasts isolated in humans, (ii) provide details regarding the specific anatomical locations where they have been detected and the clinical characteristics of the resulting infections, and (iii) provide an update on yeast taxonomy. Of the total of 239,890 fungal taxa and their associated synonyms sourced from the MycoBank and NCBI Taxonomy databases, we successfully identified 192 yeasts, including 127 Ascomycota and 65 Basidiomycota. This repertoire allows us to highlight rare yeasts and their tropism for certain anatomical sites and will provide an additional tool for diagnostic management.

Otitis externa caused by Malassezia slooffiae complicated with mastoiditis: A case report

Herein, we report a case of otitis externa caused by Malassezia slooffiae complicated with mastoiditis. A 70-year-old male complained of fever and severe otorrhea from left external auditory canal 2 months after undergoing a craniotomy to remove a hematoma. He had right-sided paralysis and undertook bed rest. Brain computed tomography revealed continuous fluid accumulation in the left mastoid air cells and middle ear from left external auditory canal in addition to leukocytosis and increased C-reactive protein level. The tympanic membrane was severely swelling. These results indicated the presence of otitis media and mastoiditis. Otorrhea culture showed large amounts of M. slooffiae. The administration of liposomal amphotericin B (L-AMB), the irrigation of external auditory canal with normal saline, and the application of topical ketoconazole ointment were started. The administration of L-AMB for 8 weeks and voriconazole, which was switched from L-AMB, for 4 weeks ameliorated his infection and he was transferred to another hospital to receive rehabilitation. From these results and his clinical course, the diagnosis of otitis externa caused by Malassezia slooffiae complicated with mastoiditis was made. And the possibility of the contamination by M. slooffiae was very low. Clinicians should be aware that M.slooffiae can provoke otological infections since M. slooffiae is the most common Malassezia sp. in external auditory canal.

Pilot study of dogs with suppurative and non-suppurative Malassezia otitis: A case series

Background

Rarely, Malassezia otitis presents as a painful, erosive otitis with an otic discharge containing Malassezia and neutrophils on cytology. There are no published reports of this type of suppurative Malassezia otitis (SMO). The role of Malassezia hypersensitivity in otitis is still unknown, and no association has been demonstrated with SMO. We compared Malassezia IgE levels, intradermal test and histology changes in SMO dogs with the more conventional Malassezia otitis (MO) presentation.

Results

Three dogs (case 1, case 2 and case 3) were diagnosed with SMO, one dog (case 4) was diagnosed with unilateral MO and unilateral SMO, and one dog (case 5) was diagnosed with MO. Only one case (case 4) with SMO/MO had a positive Intradermal Allergy Test (IDAT) and elevated IgE levels for Malassezia. Histopathology findings from SMO revealed: interface dermatitis (case 1 and 3), lymphocytic dermatitis (case 2) and chronic hyperplastic eosinophilic and lymphoplasmacytic dermatitis (case 4). Histopathology findings from MO showed perivascular dermatitis (case 4 and 5). All the cases were treated successfully.

Conclusions

SMO presents with a distinct clinical phenotype in comparison with conventional MO. No consistent aetiology could be isolated. In these clinical cases it is possible that previous treatments could have influenced the results. More research is needed to understand the possible aetiologies and the pathogenesis of SMO.

A Case of Topical Ofloxacin-Induced Otomycosis and Literature Review

The prevalence of fungal otitis externa, or otomycosis, has been increasing in recent decades. Fungi may act as primary pathogens in this condition, or they may occur as secondary infections after prolonged ototopical treatment with antibiotics, which alters the flora of the external auditory canal (EAC) and enables overgrowth of its fungal inhabitants. We report here a case of otomycosis by Candida parapsilosis, Malassezia obtusa, and Malassezia furfur as a secondary infection following prolonged otic ofloxacin treatment. To the best of our knowledge, although isolation of C. parapsilosis and M. furfur from the EAC is not uncommon, the recovery of M. obtusa has not yet been reported. We also conducted a literature review of the searchable data on PubMed concerning the isolation of Malassezia species from the human EAC.

Skull base osteomyelitis secondary to malignant otitis externa mimicking advanced nasopharyngeal cancer: MR imaging features at initial presentation

PURPOSE

Skull base osteomyelitis (SBOM) is an inflammatory process which often arises from malignant otitis externa (MOE); the diffuse skull base and adjacent soft tissue involvement may be mistaken at initial imaging for advanced nasopharyngeal carcinoma (NPC), especially if there is no prior knowledge of MOE, direct spread from the sphenoid sinus or in atypical presentations of MOE. This study aims to evaluate imaging features on MR that may differentiate SBOM from NPC.

MATERIALS AND METHODS

The MR examinations of 26 patients diagnosed with SBOM between January 1996 and January 2013 were retrospectively reviewed. Comparison was also made with the MR images of 22 consecutive patients with newly diagnosed advanced T3 and T4 NPC between July 2011 and August 2012. Imaging features in both conditions were compared, including the presence of a nasopharyngeal bulge, nasopharyngeal mucosal irregularity, lateral extension, architectural distortion (or lack thereof), increased T2 signal and enhancement patterns.

RESULTS

The most prevalent findings in SBOM were lateral extension, increased T2 signal in adjacent soft tissues, lack of architectural distortion and enhancement greater than or equal to mucosa. The combination of these 4 findings was found to best differentiate SBOM from advanced NPC, and found to be statistically significant (p<0.001).

CONCLUSION

We suggest that the combination of lateral extension, increased T2 signal, lack of architectural distortion and enhancement greater than or equal to mucosa is helpful in differentiating SBOM from advanced NPC.

Outcome predictors of treatment effectiveness for fungal malignant external otitis: a systematic review

The aim of this review is to summarise literature data on clinical aspects and traditional management of fungal malignant external otitis (FMEO), and to identify potential predictive factors of positive treatment outcome. Articles were initially selected based on their titles or abstracts. Full articles were then retrieved and further scrutinised according to predetermined criteria. Reference lists of selected articles were searched for any missed publications. The selected articles were methodologically evaluated. Of an initial 143 references, 14 were selected that focalised on the management of FMEO. The majority of studies demonstrated a correlation between treatment effectiveness, assessed as symptom resolution, and clinical and management variables: abstention from surgical debridement, absence of facial palsy, Aspergillus spp. as causative pathogen and absence of imaging findings at diagnosis and follow-up. The effectiveness of FMEO treatment depends on the assessment of cranial nerve state, the causative pathogen and imaging findings. Above all, absence of facial nerve palsy, Aspergillus spp. and absence of radiological signs at diagnosis and during follow-up correlate with symptom resolution. The fact that conservative treatment may be associated with a better outcome than surgical debridement could purely reflect that patients with more aggressive and advanced illness required debridement, whereas milder disease was treated conservatively. Thus, caution should be advised in the interpretation of data due to the need for further trials on the topic.

Malassezia-Can it be Ignored?

Genus Malassezia comprises of 14 species of “yeast like fungi,” 13 of which are lipophilic and 1 is nonlipophilic. They are known commensals and in predisposed individuals they commonly cause a spectrum of chronic recurrent infections. They rarely also cause serious illnesses like catheter-related blood stream infections, CAPD associated peritonitis etc., Though these fungi have been known to man for over 150 years, their fastidious nature and cumbersome culture and speciation techniques have restricted research. Since the last taxonomic revision, seven new species have been added to this genus. Their ability to evade the host immune system and virulence has increased the spectrum of the diseases caused by them. These agents have been implicated as causal agents in common diseases like atopic dermatitis recently. Though culture-based research is difficult, the new molecular analysis techniques and facilities have increased research in this field such that we can devote more attention to this genus to study in detail, their characteristics and their growing implications implications in the clinical scenario.

Fungal malignant otitis externa with facial nerve palsy: tissue biopsy AIDS diagnosis

Fungal malignant otitis externa (FMOE) is a serious and potentially life-threatening condition that is challenging to manage. Diagnosis is often delayed due to the low sensitivity of aural swabs and many antifungal drugs have significant side effects. We present a case of FMOE, where formal tissue sampling revealed the diagnosis and the patient was successfully treated with voriconazole, in addition to an up to date review of the current literature. We would recommend tissue biopsy of the external auditory canal in all patients with suspected FMOE in addition to routine microbiology swabs.

A rare and sinister variant of a common ailment: Fungal malignant otitis externa

A recent case report in this journal highlighted the pathophysiology and management of bacterial malignant otitis externa (MOE) (1). We describe the case of an elderly gentleman who had a delayed diagnosis of fungal MOE with advanced diseased at time of diagnosis. This case highlights the changing microbiology of this serious disease and the difficulty in diagnosis given the rarity of this form of otitis externa relative to its uncomplicated form.

The Malassezia genus in skin and systemic diseases

In the last 15 years, the genus Malassezia has been a topic of intense basic research on taxonomy, physiology, biochemistry, ecology, immunology, and metabolomics. Currently, the genus encompasses 14 species. The 1996 revision of the genus resulted in seven accepted taxa: M. furfur, M. pachydermatis, M. sympodialis, M. globosa, M. obtusa, M. restricta, and M. slooffiae. In the last decade, seven new taxa isolated from healthy and lesional human and animal skin have been accepted: M. dermatis, M. japonica, M. yamatoensis, M. nana, M. caprae, M. equina, and M. cuniculi. However, forthcoming multidisciplinary research is expected to show the etiopathological relationships between these new species and skin diseases. Hitherto, basic and clinical research has established etiological links between Malassezia yeasts, pityriasis versicolor, and sepsis of neonates and immunocompromised individuals. Their role in aggravating seborrheic dermatitis, dandruff, folliculitis, and onychomycosis, though often supported by histopathological evidence and favorable antifungal therapeutic outcomes, remains under investigation. A close association between skin and Malassezia IgE binding allergens in atopic eczema has been shown, while laboratory data support a role in psoriasis exacerbations. Finally, metabolomic research resulted in the proposal of a hypothesis on the contribution of Malassezia-synthesized aryl hydrocarbon receptor (AhR) ligands to basal cell carcinoma through UV radiation-induced carcinogenesis.

Human external ear canal as the specific reservoir of Malassezia slooffiae

The incidence of Malassezia species recovered from the external ear canal was characterized using culture medium optimized for Malassezia spp., CHROMagar Malassezia. The results of this study indicated that in healthy individuals M. slooffiae was the dominant Malassezia species followed by M. restricta.

Cutaneous malasseziasis: four case reports of atypical dermatitis and onychomycosis caused by Malassezia

BACKGROUND

This study investigates four special cases associated with Malassezia.

METHODS

The special clinical manifestations, mycologic examination, and treatment were reviewed intensively.

RESULTS

An abundance of Malassezia hyphae were found in the scales of the three cases presenting with erythematous patches and in another case presenting with dystrophic nails. Malassezia globosa was identified and confirmed by culture. Antifungal agents were effective in the treatment of all cases.

CONCLUSIONS

Malassezia is an opportunistic fungus that may induce dermatosis other than classical pityriasis versicolor. Hyphae from the lesions may be induced by a change in the microenvironment of the fungus caused by the local application of corticosteroids.

Prognostic scoring in necrotising otitis externa

Objective:

To collect and analyse data from the published literature concerning the rare condition necrotising otitis externa, in order to formulate a prognostic scoring model based on signs and symptoms.

Design:

Retrospective data collection from published literature, and binary logistic regression analysis of the effect on outcome of identified signs and symptoms.

Results:

Six factors were identified as prognostic of a poorer outcome, including facial nerve involvement, additional cranial nerve involvement, non-cranial nerve neurological involvement, extensive granulations (or oedema) in the external auditory canal, bilateral symptoms and aspergillus species as the causative organism. A four-point scoring model based on these findings is presented.

Conclusions:

A novel, systematic method of data analysis was utilised to construct a prognostic scoring model for necrotising otitis externa. This will better equip clinicians to treat this potentially fatal condition.

Update on the genusMalassezia

Malassezia yeasts are commensals of normal human skin, but also cause pityriasis versicolor, seborrhoeic dermatitis and evidence is accumulating that they play a significant role in atopic eczema/dermatitis syndrome (AEDS; formerly atopic dermatitis). The taxonomy of the genus has changed considerably and is likely to change more in the future. Our understanding of the interaction between Malassezia and the host demonstrates that it has the paradoxical ability to both stimulate and suppress the immune response directed against it and there is a fine balance in its existence at the interface between commensalism and pathogenicity.

Otogenic skull base osteomyelitis caused by invasive fungal infection

Otogenic skull base osteomyelitis (SBO) of fungal etiology is a very rare but life-threatening complication of inflammatory processes of the ear. The authors present a case of otogenic SBO caused by Aspergillus flavus in a 65-year-old man with a fatal course. Because of the encountered difficulties with the proper diagnosis and treatment, the authors reviewed the literature on the subject.

Otomycosis: subdermal growth in calcified mass

Reports on clear identification of fungi in subdermal tissue in chronic fungal external otitis are rare in recent years. Our patient was an immunocompetent adult male with an 8 year history of chronic otitis externa who presented with pustules on the external auditory canal (EAC) and necrosis and perforation of the tympanic membrane. Type I tympanoplasty was performed, but wound healing was delayed and swelling of the EAC occurred. Incision biopsy and staining (Gomori-Grocott and PAS) revealed fungal hyphae within small, calcified, subepidermal masses. A 3 month course of oral itraconazole was effective in healing the lesion. Calcification, a rarely reported finding in otomycosis, may represent a protective reaction against topical use of antifungal drugs.

The changing face of malignant (necrotising) external otitis: clinical, radiological, and anatomic correlations

Malignant (necrotising) external otitis is an invasive infection of the external auditory canal. Although elderly patients with diabetes remain the population most commonly affected, immunosuppressed individuals (eg, from HIV infection, chemotherapy, etc) are also susceptible to malignant external otitis. Pseudomonas aeruginosa is isolated from the aural drainage in more than 90% of cases. The pathophysiology is incompletely understood although aural water exposure (eg, irrigation for cerumen impaction) has been reported as a potential iatrogenic factor. The typical patient presents with exquisitely painful otorrhoea. If untreated, cranial neuropathies (most commonly of the facial nerve) can develop due to subtemporal extension of the infection. The diagnosis of malignant external otitis is based on a combination of clinical findings, an increased erythrocyte sedimentation rate, and radiographic evidence of soft tissue with or without bone erosion in the external canal and infratemporal fossa. Treatment consists of prolonged administration (6-8 weeks) of an antipseudomonal agent (typically an orally administered quinolone). With the introduction and widespread use of both oral and topical quinolones, there are reports of less severe presentation of malignant external otitis and even the emergence of ciprofloxacin resistance. Reservation of systemic quinolones for the treatment of invasive ear infections is recommended.

Temporomandibular joint involvement in malignant external otitis

OBJECTIVE

The purpose of this study was to present 6 patients with malignant external otitis (MEO) that resulted in temporomandibular joint (TMJ) involvement and to discuss the incidence, clinical presentation, and treatment modalities.

STUDY DESIGN

All patients diagnosed with MEO between 1994 and 2002 were reviewed for cases in which the TMJ was invaded by the infectious process. Only patients in whom TMJ involvement was documented radiographically and in whom the clinical course was well documented were included in this study.

RESULTS

MEO was diagnosed in 42 patients over an 8-year period; TMJ involvement was recorded in 6 patients (14%). The medical history revealed controlled type 2 diabetes mellitus in 4 of the 6 patients. All patients reported early ear symptoms, mainly otalgia and otorrhea. Local signs included an ear canal filled with granulation material, edematous overlying skin, and sensitivity to palpation. Cultures taken from the external ear were positive for either Pseudomonas aeruginosa, Staphylococcus epidermidis, Aspergillus, or Proteus mirabilis. TMJ symptoms developed between 1 and 5 months after admission and included painful periauricular swelling and trismus. In 3 patients, healing was uneventful; 3 also died of the disease.

CONCLUSIONS

TMJ involvement in MEO is associated with a resistant disease process, often with several recurrences. Prolonged administration of antibiotics is the treatment of choice. Surgical debridement of the TMJ is necessary for the positive identification of the pathogenic organism, in cases of abscess formation, or when osteomyelitic bone destruction of the condyle and glenoid fossa develop.

Malassezia species in skin diseases

Since the taxonomic revision carried out in 1996, enlarging the genus Malassezia to comprise seven different species, a number of studies have investigated from different points of view -- mycological, molecular and immunological -- the relationships of these species with the pathologies associated with lipophilic yeasts, as well as its presence in healthy skin. From these studies, it now appears clear that Malassezia globosa is the main species associated with pityriasis versicolor, which is the only cutaneous disease in which the involvement of Malassezia is undisputed. Nevertheless, this species can also be found in normal skin, in which the predominant species is Malassezia sympodialis. In the remaining dermatological disorders related to Malassezia, the role of these yeasts is controversial. In seborrhoeic dermatitis, atopic dermatitis and folliculitis, several studies have focused on the immunological aspects that could explain the pathogenic mechanism. In other diseases, such as confluent and reticulate papillomatosis, neonatal pustulosis, otitis and onychomycosis, the presence or significance of Malassezia is still a matter of dispute.

Immunology of diseases associated with Malassezia species

Malassezia species are members of the human cutaneous commensal flora, in addition to causing a wide range of cutaneous and systemic diseases in suitably predisposed individuals. Studies examining cellular and humoral immune responses specific to Malassezia species in patients with Malassezia-associated diseases and healthy controls have generally been unable to define significant differences in their immune response. The use of varied antigenic preparations and strains from different Malassezia classifications may partly be responsible for this, although these problems can now be overcome by using techniques based on recent work defining some important antigens and also a new taxonomy for the genus. The finding that the genus Malassezia is immunomodulatory is important in understanding its ability to cause disease. Stimulation of the reticuloendothelial system and activation of the complement cascade contrasts with its ability to suppress cytokine release and downregulate phagocytic uptake and killing. The lipid-rich layer around the yeast appears to be pivotal in this alteration of phenotype. Defining the nonspecific immune response to Malassezia species and the way in which the organisms modulate it may well be the key to understanding how Malassezia species can exist as both commensals and pathogens.

The spectrum of Malassezia infections in the bone marrow transplant population

A consecutive series of 3044 patients who underwent BMT at the University of Minnesota over a 25 year period were reviewed for the post-transplant occurrence of infection caused by the yeast Malassezia furfur. Six patients, ranging in age from 1 to 54 years, developed Malassezia infections at a median of 59 days post transplant. Five patients were allogeneic transplant recipients; the remaining patient had undergone autologous transplantation. A spectrum of clinical manifestations of Malassezia infection was seen in these patients, including infections of mucosal surfaces and the skin, in addition to catheter-related fungemia. Unlike many of the other more common opportunistic fungal infections in immunocompromised patients, neutropenia and the use of broad-spectrum antimicrobials do not appear to be significant risk factors for Malassezia infections in the BMT population. In addition, disseminated fungal infection despite the presence of fungemia is uncommon. Lastly, the outcome of Malassezia infections in these patients, whether folliculitis, mucosal infection, or fungemia, appears to be quite favorable, in contrast to the poorer outcome with many other fungal infections in BMT patients. Catheter removal and discontinuation of intravenous lipids are important for a successful outcome in fungemic cases.