Background: Malassezia yeasts are normal flora of the skin that are discovered in 75∼98% of health subjects, but since its association with various skin disorders have been known, many studies have been conducted in the distribution of the yeasts. Objective: To isolate, identify, and classify Malassezia yeasts from the normal human skin of Koreans by using the rapid and accurate molecular biology method (26S rDNA PCR-RFLP) which overcome the limits of morphological and biochemical methods, and to gather a basic database that will show its relation to various skin diseases. Methods: Malassezia yeasts were cultured from clinically healthy human skin using scrub-wash technique at five sites (forehead, cheek, chest, upper arm, and thigh) and swabbing technique at scalp in 160 participants comprised of 80 males and 80 females aged from 0 to 80. Identification of obtained strains were placed into the one of the 11 species by 26S rDNA PCR-RFLP. Results: An overall positive culture rate was 62.4% (599/960). As shown in the experiment groups by their age, the positive culture rate was the highest (74.2%) in the age 21∼30 and 31∼40 (89/120). In the experiment groups by different body areas, the scalp showed the highest positive culture rate of 90% (144/160). On analysis of 26S rDNA PCR-RFLP, M. globosa was the most predominant species in the age 0∼10 (32.8%), 11∼20 (28.9%), 21∼30 (32.3%). M. restricta was identified as predominant species in the age 41∼50 (27.9%), 61∼70 (31.5%) and 71∼80 (24.0%). In the age 31∼40 years, M. sympodialis was found to be the most common species (24.6%). According to body site, M. restricta was more frequently recovered in the scalp (56.8%), forehead (39.8%) and cheek (24.0%) and while M. globosa was more frequently recovered in the chest (36.8%). Higher positive culture rates of Malassezia yeasts were shown in male subjects than female counterparts in all body areas except scalp (p＜0.05). Especially in this study, M. dermatis, newly isolated Malassezia species from atopic dermatitis patient in Japan, was isolated and identified in 19 cases (1.9%) in healthy subjects. Conclusion: The key is to recognize the existence of a difference in the type of Malassezia species in different ages as well as body areas, which reflects differing skin lipid levels in various ages and different body areas. Moreover, 26S rDNA PCR-RFLP analysis which was opted in this study could provide a sensitive and rapid identification system for Malassezia species, which may be applied to epidemiological surveys and clinical practice.

Background:The yeasts of the genus Malassezia are members of the normal flora on human skin and they are found in 75∼80% of healthy adults. Since its association with various skin disorders have been known, there have been a growing number of reports that have implicated Malassezia yeast in atopic dermatitis (AD). Objective: The aim of the present study is to isolate the various Malassezia species from AD patients by using 26S rDNA (ribosomal Deoxyribonucleic acid) PCR-RFLP and to investigate the relationship between a positive Malassezia culture and the severity of AD. Methods: Cultures for Malassezia yeasts were taken from the scalp, cheek, chest, arm and thigh of 60 patients with atopic dermatitis. We used a rapid and accurate molecular biological method 26S rDNA PCR-RFLP, and this method can overcome the limits of the morphological and biochemical methods. Results: Positive Malassezia growth was noted on 51.7% of the patients with atopic dermatitis by 26S rDNA PCR-RFLP analysis. The overall dominant species was M. sympodialis (16.3%). M. restricta was the most common species on the scalp (30.0%) and cheek (16.7%). M. sympodialis (28.3%) was the most common species on the chest. The positive culture rate was the highest for the 11 ∼20 age group (59.0%) and the scalp showed the highest rate at 66.7%. There was no significant relationship between the Malassezia species and SCORing for Atopic Dermatitis (SCORAD). Conclusion: The fact that the cultured species was different for the atopic dermatitis lesion skin from that of the normal skin may be due to the disrupted skin barrier function and sensitization of the organism induced by scratching in the AD lesion-skin. But there was no relationship between the Malassezia type and the severity score. The severity score is thought to depend not on the type, but also on the quantity of the yeast.

Fibroelastolytic papulosis of the neck (FEPN) encompasses a spectrum of two disorders that were previously reported as pseudoxanthoma elasticum-like papillary dermal elastolysis (PXE-PDE) and white fibrous papulosis of the neck (WFPN). The clinical presentation of FEPN is asymptomatic to mildly pruritic whitish-yellow papules that may coalesce into cobblestone patterned plaques that resemble pseudoxanthoma elasticum (PXE). The histology is characterized by a decrease or loss of elastic fibers in the papillary dermis and this is sometimes accompanied by a minimal or nodular increase of dermal collagen fibers. We report here on a 28-year-old Korean man with asymptomatic, multiple, skin-colored to slightly yellowish, match-head sized, cobblestone-patterned papules on the neck, and these were histologically consistent with FEPN and the papules showed slightly increased dermal collagen associated with decreased and fragmented elastic fibers, elastin and tropoelastin. The pathogenesis of FEPN in this case might have been related with mild dermal inflammation, followed by fragmentation, elastolysis and increased dermal collagen.

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BackgroundAlthough acne is a common follicular inflammatory dermatosis, studies of the relationship between Malassezia yeasts and acne have rarely been conducted.ObjectiveWe sought to identify Malassezia yeasts from acne patients and establish a relationship between specific types of species of Malassezia and acne.MethodsSixty acne patients were enrolled. Each strain obtained was identified as one of eleven species by 26S rDNA PCR-RFLP. We then compared these data with those of age- and sex-matched healthy subjects.ResultsGrowth of Malassezia was evident in fewer patients with acne (50%) in comparison to controls (70.6%). M. restricta was dominant in patients with acne (23.9%), whereas M. globosa was most common (26.7%) in healthy controls. In the patients group, the rate was the highest (71.7%) in the twenties and, in terms of body site, the rate was the highest (60%) in the chest. In the control group, the rate was the highest (75.0%) in the thirties and in the forehead (85.0%).ConclusionThe detection rate of Malassezia yeasts was conspicuously low in the acne patients group. Statistically significant differences were observed between the patient and the control groups in the twenties and thirties, and in terms of body site, in the forehead and chest.