The genus Malassezia is composed of lipophilic basidiomycetous yeasts which were recently shown to consist of seven species, one lipid-independent species, M. pachydermatis and six lipid-dependent species, M. furfur, M. sympodialis, M. globosa, M. obtusa, M. restricta and M. slooffiae. Based on this classification, we will be able to analyze pathogenicity or relationship between Malassezia-related diseases and each species.

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Initiation and aggravation of several inflammatory skin diseases are associated with Malassezia furfur. These are divided into at least two groups. In one group including tinea versicolor and Malassezia folliculitis, the growth of Malassezia furfur directly triggers the development of the cutaneous lesions. In another group including atopic dermatitis, seborrheic dermatitis, and psoriasis, cutaneous lesions already developed by other mechanisms are aggravated by the growth of Malassezia furfur. Recent progress of molecular biology techniques revealed that Malassezia furfur is divided into at least seven species. Since their clinical and histological findings are quite diverse, their differences cannot be explained solely by the difference in antigenicity of each Malassezia. Instead, the cutaneous defense mechanisms against Malassezia furfur must be considered. In this article, we reviewed the mechanisms at three levels: 1) barrier functions of the uppermost layer of the skin, the stratum corneum, 2) cytokine production by epidermal keratinocytes, and 3) immune and inflammatory responses by infiltrating neutrophils and T cells.

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Pityriasis versicolor and malassezia folliculitis were studied clinically and mycologically. The main results were as follows: 1) The average age of pityriasis versicolor patients has gradually become higher. 2) Negative rates of Malassezia furfur after treatment were very high by direct examination but relatively low by culture. 3) Patients who were negative by culture on completion of treatment seldom recurred within 2 months. 4) We can evaluate the effectiveness of antifungal application by using Malassezia furfur as normal skin flora on the volunteer's back. 5) Malassezia furfur (orbiculare or ovale type) is detected in follicular contents of steroid acne and acne vulgaris, which makes it necessary to establish criteria for diagnosis of malassezia folliculitis.

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The cause of seborrhoeic dermatitis (SD) is still unknown, although many attempts have been made to relate it to infection by Malassezia. Recently Midgley, Guého & Guillot revised the genus Malassezia to 7 species. We detected Malassezia spores by direct counting using cellotape-stripped skin of healthy students or patients; we also cultured Malassezia from these subjects. Strains were classified as species according to Guillot's Tween test.
Results and Conclusion: Male students had many more spores than females. Spore numbers were not correlated to sebum levels. M. globosa or M. furfur appeared to be the main strain associated with SD. Treatment with anti-fungal agents showed that the elimination of lesions paralleled the reduction in number of Malassezia spores. In contrast to corticosteroid treatment, anti-fungal agents showed low recurrence rates. Anti-fungal agents thus have potential value as a new therapeutic agent -an alternative to corticosteroid- for the treatment of SD.

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Attention has recently been centered on fungi as aggravating factors of atopic dermatitis (AD) due to the frequent detection of IgE antibodies to fungi in patients with severe AD and to positive response of some cases of AD to antifungal therapy. Malassezia sp.: In AD patients with prominent symptoms in the head and neck, areas prone to colonization by Malassezia, the titers of specific anti-Malassezia IgE antibodies are high, which positively correlate with the total IgE value and the severity of AD. The patch test against Malassezia antigens is positive. The rate of isolation of Malassezia from the skin of AD patients is higher than that from the skin of healthy control subjects. Candida sp.: In patients with severe AD, the rate of positive skin prick tests for Candida is high, and a correlation exists between positive skin prick test results and the presence of Candida albicans in nasopharynx. However, the reactivity to Candida antigens in the patch tests is reduced, and a negative correlation is seen. There is no difference between the isolation rate of C. albicans from patients with adult-type AD and normal controls. However, AD patients give a significantly greater number of separate colonies. The range of efficacy rate of antifungal therapy of AD is reported to be 50∼65%. The efficacy rate of our own trial falls within this range. Following treatment, the rate of isolation of fungi decrease significantly, and the titers of specific antifungal IgE antibodies are not statistically significant. The clearance of fungi from the tissue following antifungal therapy probably results in the suppression of direct or indirect inflammatory reaction caused by the fungi. We therefore consider antifungal therapy as one of the second-line therapies to be administered in AD cases resistant to conventional basic therapy.

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The role of virulence factor of elastolytic proteinase produced by Aspergillus fumigatus was investigated in mice immunocompromised with cyclophosphamide (CY) to block neutrophil and lymphocyte functions or with carrageenan (CA) to block the phagocytic activity of macrophages.
These mice were infected through inhalation with the spores of elastolytic proteinase producing or nonproducing strains of A. fumigatus, and then were observed daily for 15 days or until death. Compared to CY-immunocompromised mice treated with the spores of proteinase nonproducing strains, CY-immunocompromised mice treated with the spores of proteinase producing strains had a significantly shorter survival rate. Furthermore, when treated with the spores of proteinase producing strains, CA-immunocompromised mice survived significantly longer than did CY-immunocompromised mice.
Assessment of the effect of elastolytic proteinase on rat lung showed that this enzyme induced hemorrhage of the lung, alveolar septal edema and alveolar hypertrophy due to blood neutrophil infiltration. Neither fusion nor denaturation of the elastic fiber was observed, however.
These studies have suggested that when infected with A. fumigatus, a severe lesion in bronchioli or alveoli is induced by the proteinase producing strains, and that these strains are more virulent than the proteinase nonproducing strains.

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We present results on the experimental penetration of Trichophyton mentagrophytes and T. rubrum under designated condition of humidity into human stratum corneum obtained from a healthy human heel region. When mycelia were applied to the surface side of stratum corneum and then incubated at 100% humidity, T. mentagrophytes and T. rubrum were observed in the stratum corneum on day 1 and day 1.5, respectively. At 95% humidity, T. mentagrophytes and T. rubrum penetrated on day 1.5 and day 4, and at 90% humidity, they penetrated on day 3 and day 7, respectively. At less than 85% humidity, no fungal elements of either strain were observed in stratum corneum for up to 7 days. These data suggest that at least 90% humidity is necessary for these two fungi to penetrate into stratum corneum within a few days.
However, when T. mentagrophytes was applied to the cutting side of the stratum corneum and then incubated at more than 70% humidity, the mycelia were able to penetrate within a day. The same results were obtained when T. rubrum was applied on the cutting side and incubated at 95 and 100% humidity. T. rubrum was also able to penetrate into the stratum corneum within several days at 70 and 80% humidity. These results may indicate that not only persistent moisture but also minor injuries of stratum corneum are the most important factors in the development of tinea pedis.

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Background: Phaeohyphomycosis refers to infection by dematiaceous fungi with pigmented hyphae or yeast-like cells in the tissue. In humans, this disease is usually considered to be an opportunistic infection. The causal agents of phaeohyphomycosis include numerous species belonging to different genera and they are increasing as a result of the development of intensive medical therapy.
Observation: We report the case of a 61-year-old Japanese female under corticosteroid treatment for malignant rheumatoid arthritis. An asymptomatic subcutaneous tumor developed on the back of her left foot. Histological examination of the excised material revealed mixed cell granuloma (H & E) and the presence of branched hyphal elements (periodic acid-Schiff). A fungus grown in pure culture was identified as Phaeoacremonium rubrigenum.
Conclusion: The hyphomycete genus, Phaeoacremonium, was proposed in 1996 by Crous et al. Three species belonging to this genus have been isolated from clinical specimens: P. inflatipes, from a human toenail, human synovial fluid and human mycetoma of the foot, P. parasiticum, from a subcutaneous lesion on a kidney transplant patient and several other sources, and P. rubrigenum, from a human patient with pneumonia. To our knowledge, however, this is the first report of phaeohyphomycosis caused by Phaeoacremonium rubrigenum.

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The authors surveyed the present situation for imported (introduced) mycoses from papers published in Japan as of the end of October, 1998. There were 16 cases of coccidioidomycosis, 22 of histoplasmosis, 13 of paracoccidioidomycosis and one of penicilliosis marneffei. In coccidioidomycosis the ages ranged from 17 to 55, for 14 males and two females. There were eight cases of primary pulmonary coccidioidomycosis and the remaining eight were of the disseminated type, of which two were fatal. For histoplasmosis, the ages ranged from 17 to 74 of which five cases were female and 17 male. They consisted of 13 pulmonary histoplasmosis, seven disseminated type and two cutaneous type. All cases of the disseminated type died. All of the patients with paracoccidioidomycosis were infected in Latin American countries. They consisted of 12 males and one female, and the ages ranged from 34 to 68. The clinical types were dominated by mucocutaneous-lymphangitic paracoccidioidomycoses (10 cases). A single case of penicilliosis marneffei (38 years old, male) was reported very recently. The case was complicated by AIDS and became critical. Blastomycosis has not yet been reported.
This survey indicates that the number of the imported mycoses in Japan is increasing. It is necessary for the responsible authorities to take counter measures to cope with this situation.

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