Seborrhoeic dermatitis and Pityrosporum (Malassezia) folliculitis: characterization of inflammatory cells and mediators in the skin by immunohistochemistry

Dermatite seborreica

A dermatite seborreica é uma doença eritêmato-escamativa de caráter crônico-recidivante que acomete entre 1 e 3% da população geral dos Estados Unidos. Possui dois picos de incidência - o primeiro, durante os três primeiros meses de vida, e o segundo, a partir da puberdade, atingindo seu ápice entre os 40 e 60 anos de idade. Os indivíduos HIV positivos têm maior prevalência da doença, que apresenta maior intensidade e tendência à refratariedade ao tratamento. Doenças neurológicas e outras doenças crônicas também estão associadas ao desenvolvimento da dermatite seborreica. Como mecanismo fisiopatogênico, reconhece-se que o fungo Malassezia sp., presente na pele de indivíduos suscetíveis, leve a uma irritação não-imunogênica a partir da produção de metabólitos à base de ácidos graxos insaturados deixados na superfície cutânea. Este artigo faz uma revisão da literatura sobre dermatite seborreica, com ênfase nos aspectos imunogenéticos, formas clínicas e tratamento.

Could Malassezia yeasts be implicated in skin carcinogenesis through the production of aryl-hydrocarbon receptor ligands?

Malassezia yeasts are found on the skin of all humans and many warm-blooded animals. In vitro they have the ability to synthesize potent ligands (indolo[3,2-b]carbazole, malassezin and indirubin) of the aryl-hydrocarbon receptor (AhR; synonym: dioxin receptor) when the sweat contained L-tryptophan is used as the single nitrogen source. The production of these AhR-ligands has been associated with pathogenic strains of a certain Malassezia species (Malassezia furfur) but recent evidence shows that this property is widely distributed in almost all currently known Malassezia species. AhR is associated with carcinogenesis and the potential connection of these ubiquitous skin symbionts, and putative pathogens, with skin neoplasia should be evaluated mainly focusing on mechanisms related to the distinctive ability of the yeast to produce potent AhR ligands.

HYPOTHESIS

Synthesis of available pertinent data show a possible link between Malassezia produced AhR ligands and skin carcinogenesis, particularly of basal cell carcinoma (BCC). BCCs are almost exclusively observed in animal species colonized by Malassezia. In humans and animals there is overlapping in the skin regions colonized by this yeast and affected by BCC. The potent AhR ligands synthesized by pathogenic Malassezia strains could contribute to tumor promotion by: modification of the UV radiation carcinogenesis, alterations in the salvage/survival of initiated tumor cells, inhibition of cell senescence, interaction with vitamin D metabolism, promotion of immune tolerance and finally pro-carcinogenic modulation of cell cycle progression and apoptosis.

Impression cytology and ocular surface characteristics in patients with seborrhoeic dermatitis

PURPOSE

To evaluate the clinical findings, tear film functions and ocular surface changes in patients with seborrhoeic dermatitis.

METHODS

This prospective study involved 63 patients with seborrhoeic dermatitis (Group 1) and 65 control subjects (Group 2). Best-corrected visual acuity measurement, slit-lamp examination, Schirmer I test, tear film break-up time (BUT), Rose Bengal staining and conjunctival impression cytology were performed in all patients. Subjective ocular complaints were scored using an Ocular Surface Disease Index (OSDI) questionnaire. Results between the two groups were compared.

RESULTS

In group 1, meibomitis, blepharitis and conjunctival hyperemia were seen significantly more frequently than in group 2 (p < 0.001). Impression cytology revealed grade 0 changes in 25 (39.6%) eyes, grade 1 changes in 22 (34.9%) eyes, grade 2 changes in 13 (20.6%) eyes and grade 3 changes in 3 (4.7%) eyes in group 1, whereas grade 0 changes in 48 (73.8%) eyes, grade 1 changes in 11 (16.9%) eyes and grade 2 changes in 6 (9.2%) eyes were seen in group 2 (p = 0.032). Mean goblet cell density was 795 ± 55 cells/mm(2) in group 1 and 1820 ± 100 cells/mm(2) in group 2 (p < 0.001). Mean Schirmer I and mean BUT results were statistically lower in group 1 than in group 2 (p = 0.043 and p < 0.001, respectively). Mean Rose Bengal scores and mean OSDI scores were statistically higher in group 1 than in group 2 (p = 0.002 and p < 0.001, respectively).

CONCLUSIONS

Our data show that patient with seborrhoeic dermatitis has decreased tear production, tear film instability and significant degeneration of the ocular surface epithelium, compared with normal subjects.

New insights into HIV-1-primary skin disorders

Since the first reports of AIDS, skin involvement has become a burdensome stigma for seropositive patients and a challenging task for dermatologist and infectious disease specialists due to the severe and recalcitrant nature of the conditions. Dermatologic manifestations in AIDS patients act as markers of disease progression, a fact that enhances the importance of understanding their pathogenesis.

Broadly, cutaneous disorders associated with HIV type-1 infection can be classified as primary and secondary. While the pathogenesis of secondary complications, such as opportunistic infections and skin tumours, is directly correlated with a decline in the CD4⁺ T cell count, the origin of the certain manifestations primarily associated with the retroviral infection itself still remains under investigation.

The focus of this review is to highlight the immunological phenomena that occur in the skin of HIV-1-seropositive patients, which ultimately lead to skin disorders, such as seborrhoeic dermatitis, atopic dermatitis, psoriasis and eosinophilic folliculitis. Furthermore, we compile the latest data on how shifts in the cytokines milieu, impairments of the innate immune compartment, reactions to xenobiotics and autoimmunity are causative agents in HIV-1-driven skin diseases. Additionally, we provide a thorough analysis of the small animal models currently used to study HIV-1-associated skin complications, centering on transgenic rodent models, which unfortunately, have not been able to fully unveil the role of HIV-1 genes in the pathogenesis of their primarily associated dermatological manifestations.

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.

Photodynamic therapy: new treatment for recalcitrant Malassezia folliculitis

BACKGROUND

Malassezia folliculitis commonly has been treated with oral antifungal medications. However, it has many therapeutic weaknesses such as infection relapse, drug resistance, or adverse effects like hepatotoxicity and gastrointestinal discomfort. Hence, there remains an ongoing need for alternative treatments for recalcitrant Malassezia folliculitis. Recently, many dermatologists suggest photodynamic therapy (PDT) as an alternative therapeutic option for its antimicrobial effect.

OBJECTIVE

To investigate the efficacy of methyl 5-aminolevulinic acid (MAL)-PDT for the treatment of recalcitrant Malassezia folliculitis.

MATERIALS AND METHODS

Six Korean patients aged 23-47 years with recalcitrant Malassezia folliculitis were enrolled in this study. The patients enrolled in this study either refused oral medication or were unable to take oral antifungal agents due to hepatotoxicity concerns. Thus, we offered these patients MAL-PDT as an alternative treatment option. For all patients, photographs of the lesion(s) were taken prior to initiating treatment. MAL cream (Metvix, Galderma, France) was applied to each lesion (located on the patients' trunks) and covered with an adhesive occlusive dressing polyurethane film (Tegaderm, 3M Healthcare, St. Paul, MN). After 3 hours, the cream was wiped off and illumination was performed immediately thereafter with non-coherent red light using light-emitting diodes (Aktilite lamp, PhotoCure, Oslo, Norway, average wavelength 630 nm, light dose 37 J/cm(2)). Illumination was performed for 7.5 minutes. Patients underwent totally three sessions of MAL-PDT at 2-week intervals. One month after the last PDT treatment, patients returned to the hospital and lesions were photographed.

RESULTS

After three sessions of MAL-PDT, inflammatory lesions had decreased and improved obviously in four patients, had improved slightly in one patient, and had not improved in one patient.

CONCLUSION

MAL-PDT may be an effective treatment option for patients with recalcitrant Malassezia folliculitis. However, the data on MAL-PDT are still limited, and additional controlled trials including multiple patients will be necessary to verify the results of this pilot study.

Malassezia folliculitis is caused by cutaneous resident Malassezia species

Malassezia folliculitis [MF] is caused by the invasion of hair follicles by large numbers of Malassezia cells, but it remains unclear which Malassezia species are involved in the disease. To clarify this situation, Malassezia species isolated from lesions of MF patients were analyzed by both culture and non-culture methods. In addition, Malassezia species recovered from the non-lesion areas of the skin of MF patients and skin samples of healthy subjects were included in this study. The test population consisted of 32 MF patients and 40 healthy individuals. The lesions were obtained using a comedone extractor, while swabs were employed to obtain skin samples from non-lesion areas of the patients and healthy subjects. Malassezia DNA was analyzed using a real-time PCR technique. The detection limit of the culture method was 5 CFU/cm(2) as opposes 50 cells/cm(2) with non-culture procedures. The predominant species recovered from MF lesions were M. globosa and M. sympodialis by culture method analysis, and M. restricta, M. globosa, and M. sympodialis with non-culture methods. These results were in agreement with those found with samples from non-lesion skin areas of MF patients and healthy subjects. This study clarified that MF is caused by Malassezia species that are part of the cutaneous microflora and not by exogenous species.

Distribution of Malassezia species in seborrhoeic dermatitis: correlation with patients' cellular immune status

Malassezia species are implicated in the pathogenesis of seborrhoeic dermatitis (SD), but the relationship between each species and the disorder remains unclear. It is hypothesised that the pathogenesis of SD has an immune component, which is supported by the increased incidence in patients with immunosuppressive disorders. The purpose of our study was to analyse the prevalence of Malassezia species in lesional skin of SD, and to assess the distribution of the species according to severity of the disease and cellular immune status of the patients. Forty SD patients with scalp involvement were included in the study. The samples were obtained by scraping the skin surface of the scalp and then incubated on Sabouraud dextrose agar and modified Dixon agar. The yeasts isolated were identified by their morphological and physiological properties according to the method of Guillot et al. In addition, we performed two-colour flow cytometry analysis to investigate the lymphocyte subpopulations in the peripheral blood. The most commonly isolated species was Malassezia restricta (27.5%), followed by Malassezia globosa (17.5%) and Malassezia slooffiae (15%). We demonstrated low helper/suppressor ratios in 70% patients, because of an increase in the suppressor T-cell population, suggesting an impaired cellular immunity. However, we found no significant difference in the distribution of isolated Malassezia species according to the severity of the scalp involvement and changes in the peripheral blood lymphocyte subpopulations.

Role of topical calcineurin inhibitors in the treatment of seborrheic dermatitis: a review of pathophysiology, safety, and efficacy

Seborrheic dermatitis (SD) is characterized by erythematous pruritic patches and plaques with greasy scale that occur in sebaceous areas. It is common, affecting up to 3% of the population. Past treatments have relied on a wide variety of anti-inflammatory and antifungal agents, but corticosteroids have limited use because of long-term adverse effects. Topical calcineurin inhibitors provide a safe alternative for the treatment of SD, as these drugs block the inflammatory cascade involved in the disease process and pose no risk of skin atrophy. Studies of topical pimecrolimus and tacrolimus in the treatment of SD have found that improvement occurred within 2 weeks, and if SD recurred after stopping treatment, it was significantly less severe. There have been no studies of the comparative efficacy of pimecrolimus versus tacrolimus for the treatment of SD. Common adverse effects of mild burning and irritation have been associated with the use of both of these agents. Safety profile studies are limited to studies of atopic dermatitis, which show no increase in infection rate, photocarcinogenicity, or signs of immunosuppression in patients using topical calcineurin inhibitors for long-term treatment. This article reviews the clinical trials of pimecrolimus and tacrolimus in the treatment of SD, focusing on efficacy and safety.

Seborrheic dermatitis flare in a Dutch male due to commensal Malassezia furfur overgrowth

This is a case of seborrheic dermatitis (SD) barbae from which Malassezia furfur (M. furfur) was isolated. The patient was a 57-year-old Dutch male, who was hospitalized for fever and weakness of extremities. He presented with symmetrical erythema with an abundance of greasy chaffy scales on his beard area. No reasons were detected for his fever following a routine search. M. furfur was identified through mycological examination, including direct microscopic examination, culture, Tween test, esculine splitting test and DNA sequencing, of samples from the skin lesions. The patient was treated with oral itraconazole capsules (200 mg, b.i.d. for 8 days, then 200 mg o.d. for 13 days), washing his scalp and face with 2% ketoconazole shampoo (once a day) and topical application of a cream containing 1% naftifine hydrochloride and 0.25% ketoconazole (b.i.d.). After treatment the fever subsided and the SD lesion gradually healed. M. furfur was not isolated again from skin scrapings and 7 days later therapy was terminated and no recurrence was noted after one week follow-up since the cessation of treatment.

Anti-inflammatory effects of lithium gluconate on keratinocytes: a possible explanation for efficiency in seborrhoeic dermatitis

Topical lithium (Li) gluconate has a beneficial effect on seborrhoeic dermatitis (SD), unlike oral lithium (Li) used in psychiatry. SD is an inflammatory dermatitis associated, in most of cases, with colonization by lipophilic yeasts of the genus Malassezia. However, the exact mechanism of action of Li gluconate in SD still remains unknown. The aim of our study was to investigate the effect of topical Li on cytokine secretion and innate immunity. For this purpose, we investigated first the modulatory effect of Li on two pro-inflammatory and two anti-inflammatory cytokine secretion and second, the modulatory effect of Li on Toll-like receptor (TLR) 2 and 4 expression by unstimulated and stimulated keratinocytes. Two different skin models were used: keratinocytes in monolayer and skin explants. In some of them, inflammation was induced with LPS (1 mug/ml) or zymosan (2 mg/ml). Then the skin models were incubated with Li gluconate (Labcatal*, Montrouge, France) at three different concentrations (1.6, 3, 5 mM) determined according to viability MTT test. Expression of TNFalpha, IL6, IL10, TGFbeta1, TLR2 and TLR4 was detected by immunohistochemistry (IHC). Cytokines were quantified by ELISA methods. Our results showed that the effect of Li on keratinocytes is dose-dependent. At low concentration (1.6 mM), Li enhanced TNFalpha secretion, whereas, at higher concentration (5 mM), Li significantly enhanced IL10 expression and secretion. However, there was no significant modulation of Li on IL6 and TGFbeta1 secretion. Moreover, Li at 5 mM significantly decreased TLR2 and TLR4 expressions by differentiated keratinocytes. As Li concentration during topical treatment is probably closer to 5 mM than to 1 mM, the therapeutic effect of Li gluconate in DS may be explained by two anti-inflammatory actions: an increased expression and secretion of IL10 and a decreased expression of TLR2 and TLR4 by keratinocytes. The diminution of TLR2 expression by Li may not allow MF to trigger inflammation response in lesional skin.

Molecular Analysis of Malassezia Microflora in Seborrheic Dermatitis Patients: Comparison with Other Diseases and Healthy Subjects

Malassezia species colonize the skin of normal and various pathological conditions including pityriasis versicolor (PV), seborrhoeic dermatitis (SD) and atopic dermatitis (AD). To elucidate the pathogenic role of Malassezia species in SD, Malassezia microflora of 31 Japanese SD patients was analyzed using a PCR-based, culture-independent method. Nested PCR assay using the primers in the rRNA gene indicated that the major Malassezia species in SD were M. globosa and M. restricta, found in 93 and 74% of the patients, respectively. The detection rate and number of each species varied similarly in SD, PV and healthy subjects (HSs), whereas AD showed higher values. Real-time PCR assay showed that the lesional skin harbored approximately three times the population of genus Malassezia found in nonlesional skin (P<0.05), and that M. restricta is a significantly more common species than M. globosa in SD (P<0.005). Genotypic analysis of the rRNA gene showed that the M. globosa and M. restricta from SD patients fell into specific clusters, and could be distinguished from those collected from HSs, but not from those colleted from AD patients. Our results indicate that certain strains of M. restricta occur in the lesional skin of SD patients.

AhR ligands, malassezin, and indolo[3,2-b]carbazole are selectively produced by Malassezia furfur strains isolated from seborrheic dermatitis

Malassezia yeasts are connected with seborrheic dermatitis (SD) whereas M. furfur pathogenicity is associated with the production of bioactive indoles. In this study, the production of indoles by M. furfur isolates from healthy and diseased skin was compared, the respective HPLC patterns were analyzed, and substances that are preferentially synthesized by strains isolated from SD lesions were isolated and characterized. Malassezin, pityriacitrin, indole-3-carbaldehyde, and indolo[3,2-b]carbazole (ICZ) were isolated by HPLC from extracts of M. furfur grown in L-tryptophan agar, and identified by nuclear magnetic resonance and mass spectroscopy. Of these, ICZ, a potent ligand of the aryl hydrocarbon receptor (AhR), is described for the first time to our knowledge as a M. furfur metabolite. HPLC-photodiode array detection analysis of strain extracts from 7 healthy subjects and 10 SD patients showed that M. furfur isolates from only SD patients consistently produce malassezin and ICZ. This discriminatory production of AhR agonists provides initial evidence for a previously unreported mechanism triggering development of SD and indicates that the variable pathogenicity patterns recorded for M. furfur-associated SD conditions may be attributed to selective production (P<0.001) of measurable bioactive indoles.

Immediate hypersensitivity to Malassezia furfur in patients with atopic dermatitis

Atopic dermatitis (AD) is a chronic pruritic dermatitis that has unknown aetiology. It seems that Malassezia furfur has a role in pathogenesis of AD. The purpose of this study was to evaluate skin responses to M. furfur antigens in AD patients. Malassezia furfur was grown and the yeasts were broken. Cells were centrifuged and supernatants were used as crude extracts (CE). Protein components of CE were separated by sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE). In addition, to fractionate CE antigens, gel filtration chromatography was performed. One hundred and fifteen AD patients were selected for skin-prick test (SPT). In SDS-PAGE, CE showed a total of 19 different protein bands (10-100 kDa). Chromatographic gel filtration with M. furfur proteins showed four major fractions (F). The protein pattern of F(1) (tube no. 40) was between 22 and 100 kDa and it was selected for SPT. In SPT, 49.6% and 42.6% patients showed positive reactions with CE and F(1) antigens respectively. The most positive results were obtained in 20-29 aged group (P < 0.001). The allergens of M. furfur may have a role in AD signs; it is suggested to use F(1) antigens in allergy tests.

A new ketoconazole topical gel formulation in seborrhoeic dermatitis: an updated review of the mechanism

Seborrhoeic dermatitis (SD) is a chronic, inflammatory skin disorder, affecting areas of the head and body where sebaceous glands are most prominent and active. The disorder commonly affects hair-bearing areas of the head, including the scalp. Involvement on the face is usually limited to the hairline, eyebrows, nasolabial folds and ears, and may occur either with or without scalp involvement. Areas of the trunk where SD may occur include the body folds and the presternal area. The aetiology of SD is unknown, although hormones and the Malassezia spp., formerly known as Pityrosporum (naturally occurring yeasts), are thought to be involved in the development of the condition. SD responds to the use of antifungal medications such as ketoconazole, suggesting that the inflammation could be linked to the Malassezia spp. The mechanisms behind the therapeutic effect of ketoconazole for the management of SD form the basis of this review. The broad spectrum activity of Ketoconazole was reported in the early 1980s. Due to its potent effect against Malassezia spp. the development of ketoconazole for the treatment of various skin infections, in which a link was proposed with Malassezia spp., was initiated. Later on, a number of ancillary properties were described for ketoconazole, comprising antibacterial, anti-inflammatory, sebostatic and antiproliferative effects. The incorporation of ketoconazole in an adapted vehicle further promoted its efficacy. Recently, a new anhydrous gel containing 2% ketoconazole (Xolegel) was launched, in which all of the above properties were optimised.

Clinical efficacies of shampoos containing ciclopirox olamine (1.5%) and ketoconazole (2.0%) in the treatment of seborrhoeic dermatitis

BACKGROUND

Ciclopirox olamine (CPO) is a broad-spectrum antifungal with anti-inflammatory properties effective against the yeast implicated in seborrhoeic dermatitis, Malassezia spp. This study compared 1.5% CPO shampoo with 2.0% ketoconazole shampoo and placebo in scalp seborrhoeic dermatitis.

METHODS

A randomized, double-blind, 4-week treatment period was preceded by a 2-week run-in period and followed by a 2-week run-out period. A total of 350 patients (150 CPO, 150 ketoconazole, 50 placebo) were enrolled. Assessments included scalp area affected, the severity of scaling, erythema, itching and scaling, and overall signs and symptoms.

RESULTS

Both shampoos were significantly more effective than placebo in reducing the area affected. The mean reduction from baseline to end of treatment was 48.2 cm(2) with CPO, 41.4 cm(2) with ketoconazole and 20.0 cm(2) with placebo. Patients rated the CPO shampoo as superior to placebo (p<0.001) and ketoconazole shampoo (p<0.05) on the basis of overall signs and symptoms. Assessments of itching and scaling were also significantly in favour of the CPO shampoo over placebo at the end of treatment. All three shampoos were well tolerated.

CONCLUSIONS

CPO shampoo was superior to placebo and at least as effective as ketoconazole shampoo in treating scalp seborrhoeic dermatitis. Patients rated the overall improvement as better with CPO than with ketoconazole shampoo.

Seborrhea-like dermatitis with psoriasiform elements caused by a mutation in ZNF750, encoding a putative C2H2 zinc finger protein

We describe an Israeli Jewish Moroccan family presenting with autosomal dominant seborrhea-like dermatosis with psoriasiform elements, including enhanced keratinocyte proliferation, parakeratosis, follicular plugging, Pityrosporum ovale overgrowth and dermal CD4 lymphocyte infiltrate. We mapped the disease gene to a 0.5-cM region overlapping the PSORS2 locus (17q25) and identified a frameshift mutation in ZNF750, which encodes a putative C2H2 zinc finger protein. ZNF750 is normally expressed in keratinocytes but not in fibroblasts and is barely detectable in CD4 lymphocytes.

The Key Role of Corneocytes in Pityrosporoses

Pityrosporoses encompass various Malassezia-driven conditions. Dandruff and seborrheic dermatitis are members of this family of disorders. Their precise pathomechanisms have not been completely elucidated so far. This review focuses on the role of corneocytes in these disorders. Malassezia yeasts are not evenly distributed at the surface of the stratum corneum. Rather, they are clumped on some corneocytes while other corneocytes in their vicinity are almost free of these microorganisms. The corneocytes heavily coated by yeasts suggest a cell-related defect in the mechanisms controlling the skin biocene including the natural antimicrobial peptides and nitric oxide. Most environmental factors influencing pityrosporoses indeed affect the natural human defenses against certain microorganisms. We frame as a hypothesis that the primary defect in some Malassezia-driven disorders resides in the corneocytes and their precursor keratinocytes.

Ciclopirox 1% shampoo for the treatment of seborrheic dermatitis

Seborrheic dermatitis is a chronic superficial fungal infection of the skin, particularly affecting sites rich in sebaceous glands. Although the precise etiology of seborrheic dermatitis is uncertain, yeasts of the genus Malassezia are known to play a causative role. Ciclopirox is a broad-spectrum, hydroxypyridone-derived, synthetic antifungal agent, which also has anti-inflammatory properties. Ciclopirox is effective both in vitro and in vivo against Malassezia yeasts, making it a valuable option for the treatment of seborrheic dermatitis. Varying frequencies and concentrations of ciclopirox shampoo have been shown to be effective and safe in the treatment of seborrheic dermatitis of the scalp.

Activity of the Triazole Antifungal R126638 as Assessed by Corneofungimetry

BACKGROUND

R126638 is a novel triazole exhibiting potent in vitro and in vivo antifungal activity against fungal pathogens including dermatophytes and yeasts.

OBJECTIVE

To determine the antifungal activity in time in the stratum corneum of healthy volunteers after oral intake of R126638 at a daily dose of 100 or 200 mg for 1 week.

METHOD

Sixteen male volunteers were randomly allocated to oral treatment with either 100 or 200 mg of R126638 once daily for 1 week. Five cyanoacrylate skin surface strippings (CSSS) were obtained from the forearm of each subject before drug intake at day 1. CSSS were also collected during treatment at day 2 (24 h after the first drug intake, before the second drug intake), at day 4 (before the fourth drug intake) and at day 7 (10 h after the last drug intake). The post-treatment lingering effect was assessed at day 10 (3 days after treatment) and at day 14 (7 days after treatment). The corneofungimetry bioassay was performed on these CSSS to assess the antifungal profile of R126638. Cells of different fungal species (Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis, Candida albicans and Malassezia globosa) were deposited and cultured for 10 days on CSSS in a sterile and controlled environment. The extent of fungal growth on the stratum corneum was determined using computerized image analysis.

RESULTS

R126638 clearly reduced the growth of all tested fungal species. The onset of effects of R126638 was evidenced at day 4 when it reached statistical significance for 3 of 5 species. At day 7, significance was reached for 4 of 5 species. During the posttreatment period, R126638 remained effective for 4 of 5 species at day 10, and this activity persisted until day 14 for 2 of 5 species.

CONCLUSION

A broad spectrum antifungal activity was rapidly expressed in the stratum corneum after oral intake of R126638. The drug likely reached the upper layers of the stratum corneum by diffusion and persisted in this location for at least 7 days after treatment.

Novel application of the masson-fontana stain for demonstrating Malassezia species melanin-like pigment production in vitro and in clinical specimens

Melanin-like pigment produced in vitro and in vivo by Malassezia yeasts has not been described before. Masson-Fontana staining confirmed accumulation of black pigment on the cell walls of L-dihydroxyphenylalaline (L-DOPA)-cultured Malassezia species. Black pigment was also observed in cells and hyphae from hyperpigmented patient lesions with culture-confirmed pityriasis versicolor and seborrheic dermatitis.

Fehlendes granulozytares Infiltrat bei der Pityriasis versicolor - ein Hinweis fur eine spezifische antiinflammatorische Aktivitat des Erregers? Missing granulocytic infiltrate in pityriasis versicolor - indication of specific anti-inflammatory activity of the pathogen?

The yeast Malassezia furfur is a part of the resident flora of human skin. It causes various diseases such as pityriasis versicolor, which hardly shows signs of inflammation despite marked clinical symptoms (e.g. hypopigmentation). The pathophysiology related morphological picture might give a clue to this phenomenon. As a part of the literature data are controversial, the present study compared the inflammatory infiltrate of pityriasis versicolor with that of tinea corporis in 40 human skin preparations each from diagnostic specimens. All preparations were stained with HE and PAS. Neutrophilic granulocytes were counted in the HE stain, and hyphae and spores in the PAS stain. The number of counted cells was related to the size of the respective area and the values were compared between pityriasis and tinea corporis. Significantly, more neutrophilic granulocytes were found with tinea corporis (P > 0.01), while they were virtually not demonstrable with pityriasis versicolor. It is surprising that fungal load in the stratum corneum is significantly higher with pityriasis versicolor (P > 0.01). Obviously the immune response involving neutrophilic granulocytes does not occur despite high bacterial load. This might be explained by reduced immunogenicity because of high content of lipids in the cell membrane. Furthermore, pityriarubins that are produced during tryptophan metabolism might be involved, which, in a stimulus-dependent manner, can suppress the ROS production of neutrophilic granulocytes in vivo.

Corneofungimetry Bioassay on Malassezia spp. under Ketoconazole and Desonide Influences

BACKGROUND

Glucocorticoids can boost some Malassezia-driven dermatoses. However, both antifungals and topical corticosteroids improve lesions of seborrheic dermatitis.

OBJECTIVE

To revisit the topical activity of the antifungal ketoconazole and the corticosteroid desonide on Malassezia growth on human stratum corneum.

MATERIAL AND METHODS

The computer-assisted corneofungimetry bioassay was used to compare the growth of M. furfur, M. globosa and M. restricta on human stratum corneum coated with olive oil. Four blinded gel formulations were tested. They contained either 2% ketoconazole, 0.05% desonide or a combination of 2% ketoconazole and 0.05% desonide; one gel was unmedicated. Untreated stratum corneum and specimens coated with a 2% ketoconazole cream were used as negative and positive comparators, respectively. A total of 45 samples (15 M. furfur, 15 M. globosa, and 15 M. restricta) were used for each test formulation in this randomized, double-blind study.

RESULTS

The 2% ketoconazole gel and cream and the combination of 2% ketoconazole and 0.05% desonide formulation abated similarly and significantly the M. furfur, M. globosa and M. restricta growth. The 3 species were similarly sensitive to these formulations. By contrast, no significant inhibitory effect was yielded by the 0.05% desonide gel and the vehicle.

CONCLUSION

The presence of 0.05% desonide does not impair or improve the Malassezia susceptibility to 2% ketoconazole when growing on lipid-enriched human stratum corneum.

Oral itraconazole for the treatment of seborrhoeic dermatitis: an open, noncomparative trial

BACKGROUND

Seborrhoeic dermatitis is an inflammatory cutaneous disorder in which the colonization of the affected area by Malassezia has been proved to play a key role.

OBJECTIVE

To perform a noncomparative open clinical study with oral itraconazole capsule (200 mg/day x 7 days) and consecutive usage 200 mg/day for the first 2 days of the following 2 months in patients with seborrhoeic dermatitis.

METHODS

Twenty-nine patients were enrolled to determine the efficacy and safety of oral itraconazole. The patients were evaluated according to itching, burning, erythema, desquamation and seborrhoea, each scored on a 0-4 scale on days 15 (T15), 30 (T30), 60 (T 60) and 90 (T90). Itraconazole capsule 100 mg was given twice a day for 1 week and then, after a 3-week interval, patients used itraconazole capsule 200 mg/day for the first 2 days of the following 2 months. The clinical response was graded as markedly effective, effective, moderate or ineffective.

RESULTS

A clinical improvement (evaluated as markedly effective or effective) was observed in 23 patients (83%) at T15, 21 (76%) at T30, 20 (72%) at T60 and 17 (61%) at T90. At baseline, the mean +/- SD total clinical scores were 10.44 +/- 2.45, 1.98 +/- 0.5, 2.97 +/- 1.12, 3.15 +/- 1.74 and 3.30 +/- 1.90 at T0, T15, T30, T60 and T90, respectively. Compared with baseline values, itraconazole capsule significantly reduced the mean +/- SD total score as well as individual erythema and desquamation (Wilcoxon's signed test-two tailed) (P < 0.0001). No drug-related systemic adverse event was observed during the study.

CONCLUSIONS

Seborrhoeic dermatitis shows marked reduction in inflammation when treated with itraconazole. The anti-inflammatory activity of oral itraconazole and efficacy on Malessezia suggests that itraconazole capsule will be first oral treatment option in future in severe seborrhoeic dermatitis.

Prevalence of scalp scaling in prepubertal children

OBJECTIVE

To determine the prevalence and most common etiologies of scalp scaling in infants and prepubertal children and the specificity of head and neck lymphadenopathy for the diagnosis of tinea capitis associated with scalp scaling.

DESIGN/METHODS

A cross-sectional study of 300 children, 200 from an urban general pediatric practice and 100 from 2 urban pediatric dermatology practices, was conducted. Half of the subjects were <2 years old, and half were 2 to 10 years old. Demographic data, medical history, and clinical data noting the presence of scalp scaling and other scalp signs and symptoms, as well as adenopathy of the head and neck, were collected.

RESULTS

Scalp scaling was seen in 66 (22%) children. There was an insignificantly higher prevalence of scalp scaling in those <2 years old compared with the 2- to 10-year-old group. In those <2 years old with scalp scaling, the most common diagnoses were seborrheic dermatitis (thick, adherent, greasy scale predominantly in the frontal and/or vertex areas of the scalp) and atopic dermatitis/eczema. Among those 2 to 10 years old with scalp scaling, the most common diagnoses were nonspecific (fine, white) scaling, seborrheic dermatitis, and atopic dermatitis/eczema. Nine (3%) patients were culture-positive for a dermatophyte, all of whom were black, and grew Trichophyton tonsurans. More than half (52.7%) of all patients had head and neck adenopathy. The presence of posterior nodes was significantly associated with atopic dermatitis/eczema and marginally associated with a positive dermatophyte culture. The presence of scalp scaling plus posterior adenopathy was significantly associated with seborrheic dermatitis and a positive dermatophyte culture in the entire study population and with atopic dermatitis in the pediatric dermatology clinics.

CONCLUSIONS

Scalp scaling was common in children 0 to 10 years old. Infantile-type seborrheic dermatitis was noted in both age groups: it was 3 times as likely in children <2 years old (18%) than in those 2 to 10 years old (6%). Contrary to traditional teaching, seborrheic dermatitis can be found in preadolescent children. Atopic dermatitis/eczema was associated with scalp scaling in both age groups. Head and neck adenopathy was very common and nonspecific for any 1 diagnosis. Posterior adenopathy with concurrent scalp scaling was significantly associated with seborrheic dermatitis, a positive dermatophyte culture, and atopic dermatitis. In this nonselected pediatric population, scalp scaling with adenopathy was not associated exclusively with tinea capitis.

Skin diseases associated with Malassezia species

The yeasts of the genus Malassezia have been associated with a number of diseases affecting the human skin, such as pityriasis versicolor, Malassezia (Pityrosporum) folliculitis, seborrheic dermatitis and dandruff, atopic dermatitis, psoriasis, and--less commonly--with other dermatologic disorders such as confluent and reticulated papillomatosis, onychomycosis, and transient acantholytic dermatosis. Although Malassezia yeasts are a part of the normal microflora, under certain conditions they can cause superficial skin infection. The study of the clinical role of Malassezia species has been surrounded by controversy because of their fastidious nature in vitro, and relative difficulty in isolation, cultivation, and identification. Many studies have been published in the past few years after the taxonomic revision carried out in 1996 in which 7 species were recognized. Two new species have been recently described, one of which has been isolated from patients with atopic dermatitis. This review focuses on the clinical, mycologic, and immunologic aspects of the various skin diseases associated with Malassezia. It also highlights the importance of individual Malassezia species in the different dermatologic disorders related to these yeasts.

Etiology and management of Seborrheic dermatitis

Seborrheic dermatitis (SD) is a common dermatological disorder that varies greatly in severity between individuals and with time. The etiology of this disease is poorly understood. Early investigators focused on the role of Malassezia (previously Pityrosporum) yeasts in the development of SD. Some researchers have hypothesized that there is an immunological component to SD and that this disease is caused by an altered immune response to Malassezia yeasts. However, other researchers view this condition as the result of hyperproliferation. Both antifungal and anti-inflammatory preparations have been used to treat SD effectively and safely. The wide range of antifungal formulations available (creams, shampoos, oral drugs) provides safe, effective and flexible treatment options for SD.

Seborrheic dermatitis

Seborrheic dermatitis is a common inflammation of the skin, occurring most often on the face, scalp and chest. It is closely related to infantile seborrheic dermatitis, or diaper rash. Seborrheic dermatitis is particularly common in patients with Parkinson's disease or with HIV/AIDS. The recent resurgence of interest in Malassezia yeasts has revived the old hypothesis that seborrheic dermatitis is caused by an altered relationship between these skin commensals and the host. Moreover, the success of antifungal medications in treating seborrheic dermatitis provides new evidence for this view.

LEARNING OBJECTIVE

Upon completing this paper, the reader should be aware of the clinical presentation of seborrheic dermatitis and which populations are at particular risk of developing this disorder. In addition, s/he will be aware of the role of Malassezia yeasts in seborrheic dermatitis and the way in which knowledge of the importance of these yeasts has altered the treatment of this disorder.

Role of antifungal agents in the treatment of seborrheic dermatitis

Seborrheic dermatitis is a superficial fungal disease of the skin, occurring in areas rich in sebaceous glands. It is thought that an association exists between Malassezia yeasts and seborrheic dermatitis. This may, in part, be due to an abnormal or inflammatory immune response to these yeasts. The azoles represent the largest class of antifungals used in the treatment of this disease to date. In addition to their antifungal properties, some azoles, including bifonazole, itraconazole, and ketoconazole, have demonstrated anti-inflammatory activity, which may be beneficial in alleviating symptoms. Other topical antifungal agents, such as the allylamines (terbinafine), benzylamines (butenafine), hydroxypyridones (ciclopirox), and immunomodulators (pimecrolimus and tacrolimus), have also been effective. In addition, recent studies have revealed that tea tree oil (Melaleuca oil), honey, and cinnamic acid have antifungal activity against Malassezia species, which may be of benefit in the treatment of seborrheic dermatitis. In cases where seborrheic dermatitis is widespread, the use of an oral therapy, such as ketoconazole, itraconazole, and terbinafine, may be preferred. Essentially, antifungal therapy reduces the number of yeasts on the skin, leading to an improvement in seborrheic dermatitis. With a wide availability of preparations, including creams, shampoos, and oral formulations, antifungal agents are safe and effective in the treatment of seborrheic dermatitis.

Itraconazole in the treatment of seborrheic dermatitis: a new treatment modality

BACKGROUND

Due to the high rate of recurrence, seborrheic dermatitis (SD) represents a therapeutic problem.

AIM

To evaluate the role of oral itraconazole in the treatment of SD.

PATIENTS AND METHODS

Thirty-two patients with SD were enrolled in the study. All topical and oral treatments were stopped. The patients applied 1% hydrocortisone cream twice daily for 1 month. In addition, they took itraconazole, 200 mg/day, during the first week of the first month and then hydrocortisone cream was stopped and itraconazole (200 mg/day) was given on the first 2 days of the following 11 months. The patients were followed for 2 months without medicine. The severity score was measured at the initial evaluation, and at the first, 12th, and 14th months.

RESULTS

Twenty-eight patients completed the study. There was a statistically significant decrease in the mean severity score at the first, 12th, and 14th months. On the final evaluation at the 12th month, 19 of the 28 patients showed a complete improvement, and three patients showed a slight improvement.

CONCLUSIONS

This study indicates that itraconazole plays an important role in the treatment of SD.

Superficial fungal infections: an update on pityriasis versicolor, seborrheic dermatitis, tinea capitis, and onychomycosis

The recent advances in pityriasis versicolor, seborrheic dermatitis, tinea capitis and onychomycosis are reviewed. Some highlighted points include the new classification of Malassezia species, and the association of Malassezia species with seborrheic dermatitis. The use of terbinafine, fluconazole, and itraconazole for the treatment of tinea capitis is discussed. The management of onychomycosis, highlighting the high efficacy rates obtained with terbinafine when used to treat dermatophyte toenail onychomycosis, is discussed. The use of combination therapies in some circumstances to maximize cure rates is reviewed.

An open pilot study using tacrolimus ointment in the treatment of seborrheic dermatitis

Seborrheic dermatitis is generally treated with topical steroids, antifungals, or both. This pilot study was undertaken to examine the possibility of tacrolimus as a useful therapy for seborrheic dermatitis. In a single-center, open-label study, 18 consecutive patients with seborrheic dermatitis were treated with 0.1% tacrolimus for a total of 28 days or until complete clearance occurred, if sooner. Of the patients, 11 (61%) showed 100% clearance of their seborrheic dermatitis; the remaining 7 patients showed 70% to 99% clearance. The most common side effects were mild local burning and irritation.

Seborrheic dermatitis

Seborrheic dermatitis is present in 1% to 3% of immunocompetent adults, and is more prevalent in men than in women. Seborrheic dermatitis may be seen in conjunction with other skin diseases, such as rosacea, blepharitis or ocular rosacea, and acne vulgaris. Malassezia yeasts have been associated with seborrheic dermatitis. Abnormal or inflammatory immune system reactions to these yeasts may be related to development of seborrheic dermatitis. Treatment modalities for seborrheic dermatitis include keratolytic agents, corticosteroids, and more recently, antifungal agents. Antifungal agents do not carry a risk of skin atrophy or telangiectasia with prolonged use, and it is more prudent to consider antifungals than corticosteroid preparations. The wide range of antifungal formulations available (creams, shampoos, or oral) provides safe, effective, and flexible treatment options for seborrheic dermatitis.

Seborrheic dermatitis, increased sebum excretion, and Parkinson's disease: a survey of (im)possible links

The concept of skin as a mirror of parkinsonism, dates back at the beginning of the last century. Since then, much evidence has been accumulated supporting a causal association between the neurological disturbance and changes detectable on areas of the integument with the richest sebaceous gland supply, namely seborrheic dermatitis and/or seborrhea. However, the many persisting sources of perplexity weighing on some general aspects of the skin condition itself (lack of standardized diagnostic criteria, high variability of estimates of prevalence, and controversies on etiology and pathomechanisms) must have to date hampered assessment of the real nature, and significance (if any) of the links observed. The three major pathogenical pathways so far conceived in this context will be critically reviewed on the basis of evidences provided in the literature.

IgE-reactivity to seven Malassezia species

BACKGROUND

Malassezia yeasts play a role in the pathogenesis of atopic eczema/dermatitis syndrome (AEDS). The revised genus Malassezia includes several species which all are natural habitants of the human skin. In this study, we evaluated the presence of immunoglobulin E (IgE) antibodies to different Malassezia spp. in AEDS patients to allow optimization of the characterization of the IgE antibody profile of IgE-associated AEDS.

METHODS

Ninety-six adult patients, with a clinical diagnosis of AEDS, were included in the study. Seventeen of the patients had IgE antibodies to M. sympodialis, ATCC 42132 (m70 ImmunoCAP, Pharmacia, Diagnostic AB, Uppsala, Sweden). The IgE antibodies to seven Malassezia spp. were measured and inhibition immunoblotting was performed to investigate whether M. sympodialis contains all the allergen components present in the other Malassezia spp.

RESULTS

Twenty per cent of 79 AEDS patients with a negative m70 ImmunoCAP test had IgE antibodies to at least one of the other six Malassezia spp. tested. Our inhibition studies indicated that Malassezia spp. to a great extent, share allergenic determinants. However, Malassezia species also contained species-specific allergens.

CONCLUSION

The use of only one species of Malassezia is not sufficient to detect all patients IgE sensitized to Malassezia. To obtain an optimal allergen preparation both common allergenic components as well as species-specific allergens have to be considered.

Up-regulated expression of MICA and proinflammatory cytokines in skin biopsies from patients with seborrhoeic dermatitis

Seborrhoeic dermatitis is a disease of unknown etiopathogenesis that affects 5% of the population. In this study, we investigated expression of mRNA for IL-1 alpha, IL-6, IL-4, IFN-gamma, and the stress-inducible MICA molecule in skin biopsies from 12 patients with moderate to severe seborrhoeic dermatitis and 2 healthy volunteers by RT-PCR and hybridization with specific probes. Eight patients expressed INF-gamma, 2 expressed IL-6, 8 expressed IL-1 alpha, and 2 expressed IL-4 (1 with moderate disease). Eight patients expressed inflammatory cytokines (IL-1 alpha, IL-6, and/or IFN-gamma) in healthy skin. Higher cytokine mRNA in damaged vs healthy skin was also observed, suggesting the existence of an inflammation that predisposes healthy skin to develop overt disease. Up-regulated expression of MICA mRNA was observed in 8 patients. Although the pathogenesis of seborrhoeic dermatitis remains to be elucidated, expression of cytotoxicity-activating ligands (MICA), recruitment of NK cells, and a local pro-inflammatory microenvironment may facilitate the development of tissue injury.

Variability in responsiveness to irritants: thoughts on possible underlying mechanisms

Patch testing with chemical irritants almost always produces a striking variability in the intensity of reaction between individuals, even amongst normal, healthy subjects. Whilst there have been many attempts to define factors which predispose to heightened or, conversely, to diminished reactivity, the underlying cellular mechanisms responsible for the variability remain poorly understood. In this review, a number of possible explanations are proposed, with a particular emphasis on those which relate to the influence of pre-existing disease or to the genetic regulation of certain immunological and inflammatory processes.

Atopic dermatitis and fungi

Atopic dermatitis (AD) is a chronic, itching, inflammatory skin disease which is associated with asthma and/or hay fever and a familial occurrence of these conditions. Genetic factors are important in the development of AD, but the exact hereditary pathway is still unknown. Dry skin and the weakened barrier function in patients with AD is very important for the patient's reactions to irritants and other external trigger factors including microorganisms. The standard treatments are topical corticosteroids, topical immunomodulating agents, and emollients. If AD cannot be controlled by this type of treatment, systemic immunomodulating agents may be used. UVB, UVA, or psoralen-UVA may also be used for widespread severe lesions. However, some patients do not respond to these standard treatment, and then it is important to consider the role of microorganisms, house dust mites or food. The role of the Malassezia yeasts in AD, especially AD located to the head and neck region, is now documented in several papers. There are also several papers indicating the role of Candida as an aggravating factor in AD. Patients with AD also develop chronic dermatophyte infections more easily, and patients with AD and chronic dermatophyte infections may show improvement in their AD when treated with antifungal drugs.

Fast, noninvasive method for molecular detection and differentiation of Malassezia yeast species on human skin and application of the method to dandruff microbiology

Malassezia fungi have been the suspected cause of dandruff for more than a century. Previously referred to as Pityrosporum ovale, Pityrosporum orbiculare, or Malassezia, these fungi are now known to consist of at least seven Malassezia species. Each species has a specific ecological niche, as well as specific biochemical and genetic characteristics. Malassezia yeasts have fastidious culture conditions and exceedingly different growth rates. Therefore, the results of surveys of Malassezia based on culture methods can be difficult to interpret. We developed a molecular technique, terminal fragment length polymorphism analysis, to more accurately survey the ecology of Malassezia yeasts without bias from culture. This technique involves fluorescent nested PCR of the intergenic transcribed spacer (ITS) ITS I and ITS II region ribosomal gene clusters. All known Malassezia species can be differentiated by unique ITS fragment lengths. We have used this technique to directly analyze scalp samples from subjects enrolled in a demographic scalp health study. Results for subjects assigned composite adherent scalp flaking scores (ASFS) <10 were compared to those for subjects assigned composite ASFS >24. Malassezia restricta and M. globosa were found to be the predominant Malassezia species present in both groups. Importantly, we found no evidence of M. furfur in either group, indicating that M. furfur can be eliminated as the causal organism for dandruff. Both groups also showed the presence of non-Malassezia fungi. This method, particularly when it is used in combination with existing fungal ITS databases, is expected to be useful in the diagnosis of multiple other fungal infections.

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.