Treatment Outcomes for Malassezia Folliculitis in theDermatology Department of a University Hospital in Japan

Clinical characteristics and treatment outcomes of Pityrosporum folliculitis in immunocompetent patients

Pityrosporum folliculitis (PF) is a fungal acneiform disease of the hair follicles that often presents with pruritic papules and pustules on the upper body and face. This condition is commonly mistaken for acne vulgaris and can be distinguished from bacterial acne by the presence of fungal spores in the follicular lumen. Although studies have been performed to describe PF in cohorts, little work has been done to aggregate these data. Thus, the goal of this review is to describe the clinical characteristics and treatment outcomes of PF in immunocompetent patients. PubMed, Web of Science, and Embase were searched using the terms "Pityrosporum folliculitis" or "Malassezia folliculitis." All cohorts reporting PF characteristics in patients classified as immunocompetent were reviewed. A total of 15 studies were included. Majority of patients were male (64%) with the average age of presentation of 24.26 years. The most common locations of lesions were the chest (70%) and back/shoulders (69.2%). Pruritus was reported by the majority of patients (71.7%). Additionally, 40.5% of patients reported a history of unsuccessful treatment regimens. Treatment was most successful with an oral antifungal (92%), followed by a topical antifungal (81.6%). In conclusion, majority of patients with PF were younger males. Many patients were primarily treated incorrectly, suggesting the importance of proper diagnosis. PF may be distinguishable from acne vulgaris by the presence of pruritus or suggested when a new acneiform eruption develops following antibiotic therapy or immunosuppression. When properly diagnosed, majority of cases of PF achieve complete response with oral or topical antifungals.

Part 2: Understanding the role of Malassezia spp. in skin disorders: pathogenesis of Malassezia associated skin infections

INTRODUCTION

Malassezia is a major component of the skin microbiome, a lipophilic symbiotic organism of the mammalian skin, which can switch to opportunistic pathogens triggering multiple dermatological disorders in humans and animals. This phenomenon is favored by endogenous and exogenous host predisposing factors, which may switch Malassezia from a commensal to a pathogenic phenotype.

AREA COVERED

This review summarizes and discusses the most recent literature on the pathogenesis of Malassezia yeasts, which ultimately results in skin disorders with different clinical presentation. A literature search of Malassezia pathogenesis was performed via PubMed and Google scholar (up to May 2023), using the following keywords: Pathogenesis and Malassezia;host risk factors and Malassezia, Malassezia and skin disorders; Malassezia and virulence factors: Malassezia and metabolite production; Immunology and Malassezia.

EXPERT OPINION

Malassezia yeasts can maintain skin homeostasis being part of the cutaneous mycobiota; however, when the environmental or host conditions change, these yeasts are endowed with a remarkable plasticity and adaptation by modifying their metabolism and thus contributing to the appearance or aggravation of human and animal skin disorders.

Position statement: Recommendations on the diagnosis and treatment of Malassezia folliculitis

Malassezia is a lipophilic yeast that is a part of the human mycobiome. Malassezia folliculitis appears when the benign colonization of the hair follicles, by the Malassezia yeasts, becomes symptomatic with pruritic papules and pustules. Although Malassezia folliculitis is common in hospital departments, diagnosing and treating it varies among dermatologists and countries. The European Academy of Dermatology and Venereology Mycology Task Force Malassezia folliculitis working group has, therefore, sought to develop these recommendations for the diagnosis and management of Malassezia folliculitis. Recommendations comprise methods for diagnosing Malassezia folliculitis, required positive findings before starting therapies and specific treatment algorithms for individuals who are immunocompetent, immunocompromised or who have compromised liver function. In conclusion, this study provides a clinical strategy for diagnosing and managing Malassezia folliculitis.

The Prevalence, Associated Factors, and Clinical Characterization of Malassezia folliculitis in Patients Clinically Diagnosed with Acne Vulgaris

BACKGROUND

The clinical presentation of Malassezia folliculitis (MF) can imitate acne vulgaris (AV), making it difficult to distinguish between the two conditions. Moreover, MF can coexist with AV in the same patient. The incidence of MF in patients clinically diagnosed with AV may be underestimated. This study aimed to determine the prevalence, associated factors, and clinical characterization of MF patients diagnosed with AV.

MATERIALS AND METHODS

Three hundred twenty new acne patients were questioned regarding general information, including age, sex, itchy symptoms, and past treatment history with antibiotics and steroids within four weeks. Clinical presentations of AV (location and severity), dandruff, and seborrheic dermatitis were examined by a dermatologist. Cytologic studies to determine the abnormal proliferation of Malassezia yeasts were performed from pustules or, in the absence of pustules, comedo-like papules, and comedones. The smears were stained with methylene blue and evaluated under a light microscope by the researcher.

RESULTS

The prevalence of MF in patients clinically diagnosed with AV was 28.8% (95% Confidence interval: CI = 23.8% - 33.7%), which can be classified as 24.7% were AV with MF and the remaining 4.1% were MF only. This study revealed that patients diagnosed with MF were 7.38 times more likely to have itchy symptoms than patients diagnosed with AV. MF patients had 8.89 times and 9.17 times higher risk of acneiform lesions on the scalp/ hairline and upper back than those who did not have MF, respectively.

CONCLUSION

This present study revealed a high prevalence of MF in patients clinically diagnosed with AV. Dermatologists should be aware of MF when encountering AV patients with acneiform lesions on the scalp/ hairline and upper back with pruritus. Diagnosis based on clinical presentations alone may lead to misdiagnosis. Methylene blue staining is easy to perform and beneficial to diagnose MF.

Malassezia: Zoonotic Implications, Parallels and Differences in Colonization and Disease in Humans and Animals

Malassezia spp. are commensals of the skin, oral/sinonasal cavity, lower respiratory and gastrointestinal tract. Eighteen species have been recovered from humans, other mammals and birds. They can also be isolated from diverse environments, suggesting an evolutionary trajectory of adaption from an ecological niche in plants and soil to the mucocutaneous ecosystem of warm-blooded vertebrates. In humans, dogs and cats, Malassezia-associated dermatological conditions share some commonalities. Otomycosis is common in companion animals but is rare in humans. Systemic infections, which are increasingly reported in humans, have yet to be recognized in animals. Malassezia species have also been identified as pathogenetic contributors to some chronic human diseases. While Malassezia species are host-adapted, some species are zoophilic and can cause fungemia, with outbreaks in neonatal intensive care wards associated with temporary colonization of healthcare worker’s hands from contact with their pets. Although standardization is lacking, susceptibility testing is usually performed using a modified broth microdilution method. Antifungal susceptibility can vary depending on Malassezia species, body location, infection type, disease duration, presence of co-morbidities and immunosuppression. Antifungal resistance mechanisms include biofilm formation, mutations or overexpression of ERG11, overexpression of efflux pumps and gene rearrangements or overexpression in chromosome 4.

Susceptibilities of Malassezia strains from pityriasis versicolor, Malassezia folliculitis and seborrheic dermatitis to antifungal drugs

The human pathogenic yeast genus Malassezia may be an etiological agent of skin disorders and has received considerable attention from dermatologists in recent years. To investigate the different susceptibilities of Malassezia species to four antifungal drugs, we isolated a total of 244 Malassezia strains and identified six species of Malassezia from patients with clinical skin diseases. The minimum inhibitory concentration (MIC) of the four antifungal drugs was obtained by comparing the susceptibility of the isolated Malassezia strains to four antifungal drugs (ketoconazole (KTZ), itraconazole (ITZ), fluconazole (FLC) and amphotericin B (Am B)). We demonstrated that M. furfur, M. sympodialis, M. pachydermatis and M. globosa are the most common Malassezia species in the three skin diseases. The MICs of KTZ, ITZ, FLC and Am B against M. furfur, M. sympodialis, M. pachydermatis and M. globosa ranged from 0.03 - 16 mg/L, 0.03 - 2.0 mg/L, 0.03 - 8 mg/L, and 13 - 64 mg/L, respectively. The sensitivities of Malassezia to the four antifungal drugs from high to low were ITZ ≥ KTZ > Am B > FLC. The susceptibilities of the various Malassezia species to the four antifungal drugs were different, and the susceptibility of M. furfur to KTZ was significantly different from those of the three skin diseases (pityriasis versicolor, Malassezia folliculitis and seborrheic dermatitis). Our results suggested that the MIC analysis of the four antifungal drugs would be helpful in preventing drug resistance in the clinical screening of Malassezia and choosing better antifungal drugs to treat Malassezia-associated skin diseases.

Critical synthesis of available data in Malassezia folliculitis and a systematic review of treatments

Folliculitis is an inflammatory process involving the hair follicle, frequently attributed to infectious causes. Malassezia, an established symbiotic yeast that can evolve to a skin pathogen with opportunistic attributes, is a common source of folliculitis, especially when intrinsic (e.g. immunosuppression) or extrinsic (high ambient temperature and humidity, clothing) impact on the hair follicle and the overlying skin microenvironment. Our aim was to critically review the pathophysiology and clinical characteristics of Malassezia folliculitis, to describe laboratory methods that facilitate diagnosis and to systematically review treatment options. Malassezia folliculitis manifests as a pruritic, follicular papulopustular eruption distributed on the upper trunk. It commonly affects young to middle-aged adults and immunosuppressed individuals. Inclusion into the differential diagnosis of folliculitis is regularly oversighted, and the prerequisite-targeted diagnostic procedures are not always performed. Sampling by tape stripping or comedo extractor and microscopic examination of the sample usually identifies the monopolar budding yeast cells of Malassezia without the presence of hyphae. However, confirmation of the diagnosis with anatomical association with the hair follicle is performed by biopsy. For systematic review of therapies, PubMed was searched using the search string "(malassezia" [MeSH Terms] OR "malassezia" [All Fields] OR pityrosporum [All Fields]) AND "folliculitis" [MeSH Terms] and EMBASE was searched using the search string: 'malassezia folliculitis.mp OR pityrosporum folliculitis.mp'. In total, 28 full-length studies were assessed for eligibility and 21 were selected for inclusion in therapy evaluation. Conclusively Malassezia folliculitis should be considered in the assessment of truncal, follicular skin lesions. Patient's history, comorbidities and clinical presentation are usually indicative, but microscopically and histological examination is needed to confirm the diagnosis. Adequate samples obtained with comedo extractor and serial sections in the histological material are critical for proper diagnosis. Therapy should include systemic or topical measures for the control of the inflammation, as well as the prevention of recurrences.

An update on pityrosporum folliculitis in Singapore from a single tertiary care dermatological centre

INTRODUCTION

Pityrosporum folliculitis (PF) is a common skin condition that can be misdiagnosed, especially by non-dermatologists. While the diagnosis is often made clinically, skin microscopy may be used to confirm the same. There is scant literature on the clinical epidemiology of PF globally. In Singapore, to our knowledge, one prior epidemiological study was performed in 1987. We aimed to provide an update regarding the epidemiology, diagnosis and treatment of patients with PF in Singapore.

METHODS

We performed a retrospective review of patients with clinical presentations compatible with PF, who presented to the National University Hospital dermatology clinic, Singapore, between 1 January 2011 and 31 December 2015. The medical records of patients identified as having clinical presentations that resembled PF were reviewed via the hospital written and electronic databases. Information was collected on their demographics and clinical presentation.

RESULTS

Of 375 patients identified, 214 (57.1%) patients were confirmed to have PF on Gram-stained microscopy. Of these 214 patients, most patients were in the age group 21-30 years (35.0%). The male-to-female ratio was 3:1. The lesions predominantly occurred on the trunk and back. A majority of patients presented with symptom duration over one month. 128 patients received oral antifungal treatment (59.8%), whereas 82 patients were treated with topical antifungal treatment alone (38.3%).

CONCLUSION

The typical Singapore patient with PF is a young man in the age group 21-30 years, with erythematous follicular papules or pustules over the trunk and back.

Malassezia-Associated Skin Diseases, the Use of Diagnostics and Treatment

Yeasts of the genus, Malassezia, formerly known as Pityrosporum, are lipophilic yeasts, which are a part of the normal skin flora (microbiome). Malassezia colonize the human skin after birth and must therefore, as commensals, be normally tolerated by the human immune system. The Malassezia yeasts also have a pathogenic potential where they can, under appropriate conditions, invade the stratum corneum and interact with the host immune system, both directly but also through chemical mediators. The species distribution on the skin and the pathogenetic potential of the yeast varies between different Malassezia related diseases such as head and neck dermatitis, seborrheic dermatitis, pityriasis versicolor, and Malassezia folliculitis. The diagnostic methods used to confirm the presence of Malassezia yeasts include direct microcopy, culture based methods (often a combination of morphological features of the isolate combined with biochemical test), molecular based methods such as Polymerase Chain Reaction techniques, and Matrix Assisted Laser Desorption/Ionization—Time Of Flight mass spectrometry and the chemical imprint method Raman spectroscopy. Skin diseases caused by Malassezia are usually treated with antifungal therapy and if there are associated inflammatory skin mechanisms this is often supplemented by anti-inflammatory therapy. The aim of this paper is to provide an overview of Malassezia related skin disease, diagnostic methods and treatment options.

New Developments in Bacterial, Viral, and Fungal Cutaneous Infections

PURPOSE OF REVIEW

This review highlights clinically relevant updates to common and significant bacterial, viral, and fungal cutaneous infection within the past 5 years. Recent developments are presented so that the clinician may provide evidence-based, high-quality patient care.

RECENT FINDINGS

New resistance patterns in cutaneous pathogens have recently emerged as a result of inappropriate antimicrobial use. Several new FDA-approved antimicrobials have been approved to treat such infections, including multi-drug resistant pathogens. Several organizational guidelines for cutaneous infection management have been updated with new recommendations for screening, diagnostic, and treatment strategies.

SUMMARY

Clinicians should be aware of the most recent evidence and guidelines for the management of cutaneous infections in order to reduce the emergence of antimicrobial resistance and most effectively treat their patients.

Malassezia (Pityrosporum) Folliculitis Incognito: Malessezia-associated Folliculitis Masked by Topical Corticosteroid Therapy

Malassezia (Pityrosporum) folliculitis usually appears as pruritic monomorphous papules and pustules on the upper back, chest, extensor arms and face. Acne vulgaris, bacterial folliculitis, eosinophilic folliculitis and systemic corticosteroid-induced acne can clinically mimic the fungal-caused acneiform condition. The designation incognito is used to describe tinea or scabies when the characteristic presentation is masqueraded by the application of topical corticosteroid treatment. Application of corticosteroid cream altered the morphology of the skin lesions in a man with Malassezia folliculitis. His cutaneous findings-localized areas of post-inflammatory hyperpigmentation with flattened or completely resolved follicular papules-raised the possibility of partially treated follicular eczema or follicular contact dermatitis. Pathognomonic findings from biopsies of the skin lesions established the diagnosis of Malassezia folliculitis; the condition completely resolved after treatment with topical antifungal shampoo and cream. Similar to tinea incognito and scabies incognito, folliculitis caused by Malassezia yeast in which the cutaneous morphology has been concealed by management with topical corticosteroids should be referred to as Malassezia (Pityrosporum) folliculitis incognito. 

Clinicopathological differentiation between Pityrosporum folliculitis and acneiform eruption

Distinguishing between Malassezia folliculitis (Pityrosporum folliculitis [P. folliculitis]) and acneiform eruption, based on clinicopathological features, is challenging for clinicians. In the literature, the histopathological differences between P. folliculitis and acneiform eruption lesions have been poorly described. We aimed to determine the clinicopathologic distinctions between P. folliculitis and acneiform eruption by retrospectively analyzing the histology of hematoxylin and eosin stained tissue sections obtained from 52 patients diagnosed with these lesions. The presence of fungal spores in the follicular lumen was most consistent with a P. folliculitis diagnosis (P < 0.001). However, intrafollicular inflammation (P = 0.009), irregular patterns of keratin plugging (P = 0.008), and nuclear dust in the follicular lumen (P < 0.001) favored an acneiform eruption diagnosis. These intrafollicular characteristics and inflammatory differences are believed to be caused by necrotic keratinocytes that lead to vacuolar changes in the follicular wall (P = 0.013). We did not observe any difference between P. folliculitis and acneiform eruption lesions in terms of perifollicular inflammatory cell infiltration. Our study demonstrated that significant differences exist between P. folliculitis and acneiform eruption lesions relative to the presence of necrotic keratinocytes in the follicular wall, intrafollicular characteristics, and inflammatory cell infiltrations. Necrotic keratinocytes are believed to have a key role in these differences. These findings may contribute to an improved understanding of the pathogenesis and differential diagnosis of P. folliculitis and acneiform eruption.

Topical ketoconazole: a systematic review of current dermatological applications and future developments

Introduction: Although labeling changes and market withdrawal have been implemented for oral ketoconazole (KTZ) due to serious adverse effects (AEs), topical KTZ is generally thought to be effective and safe for the treatment of superficial fungal infections. New dermatologic indications for the use of topical KTZ have arisen such as onychomycosis, blepharitis, and hair loss. This article aims to review the literature on topical KTZ's efficacy and AEs, as well as provide an overview on current insights regarding its mechanism of action and upcoming developments. Methods: A PubMed search was done to include randomized controlled trials (RCTs) focusing on the use of topical KTZ in human subjects. Results: Forty studies with 4566 patients were included in this review. Topical KTZ is clinically effective for the treatment of Malassezia-related conditions such as seborrheic dermatitis (SD) and pityriasis versicolor (PV) with a reported efficacy of 63-90% and 71-89%, respectively. Conclusions: Topical KTZ demonstrates high clinical efficacy for Malassezia-related conditions. More efficacious alternatives are now available for Tinea and Candida. Although topical KTZ is safe, clinicians should be aware that allergic contact dermatitis may occur. Further studies should be completed to investigate the use of topical KTZ for hair loss and inflammatory dermatoses.