PHÂN BỐ LOÀI MALASSEZIA SPP. TRÊN BỆNH NHÂN NẤM DA

Abstract

Objective: To determine the species distribution of pathogenic Malassezia in patients with pityriasis versicolor presenting at Ho Chi Minh City Hospital of Dermatology and Venereology. Materials and Methods: A cross-sectional descriptive study was conducted. Skin scale samples were collected from 100 patients with confirmed pityriasis versicolor at Ho Chi Minh City Dermatology Hospital, from 3/2025 to 7/2025. Results: Among 100 direct microscopy–positive samples, 54 yielded successful fungal cultures. The most frequently isolated species was M. furfur (33%), followed by M. globosa (24%) and M. dermatis (17%). Other species included M. restricta (13%) and unidentified Malassezia spp. (7%), while M. sympodialis, M. pachydermatis, and M. japonica were detected at low rates (2% each). Males predominated (68% vs. 32%). Disease duration was most commonly less than 3 months (40%), although chronic cases (>1 year) were also frequent (33%). The majority of patients experienced their first episode (63%), while single and multiple recurrences accounted for 30% and 7%, respectively. Most patients reported mild or absent pruritus (47% and 46%), whereas severe pruritus was uncommon (7%). Lesions were most frequently located on the back (55%), followed by the chest (23%) and abdomen (8%), with other sites less frequently involved. Conclusion: Malassezia furfur remains the predominant species in pityriasis versicolor, followed by M. globosa and M. dermatis, along with less common species. Culture and species identification are valuable for confirming diagnosis, providing epidemiological data, and suggesting potential associations between species and clinical features (onset, recurrence, and lesion distribution), thereby opening directions for further clinical research.