Identification of Malassezia species isolated from Iranian seborrhoeic dermatitis patients

M.T. Hedayati, Z. Hajheydari*, F. hajjar**, A. Ehsani§, T. Shokohi#, R. Mohammadpour‡

Department of Medical Mycology and Parasitology; *Department of Dermatology; **Department of Medical Mycology and Parasitology, School of Medicine, Sari (Iran) §Department of Dermatology, School of Medicine, Tehran University of Medical Sciences, Tehran (Iran) #Department of Medical Mycology and Parasitology, School of Medicine; ‡Department of Statistics, School of Health, Mazandaran University of Medical Sciences, Sari (Iran)

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• Dermatology

Abstract. – Background and Objectives: In recent years, the genus Malassezia has come to be considered important in the etiology of seborrhoeic dermatitis (SED). The aim of present study was identification of Malassezia species on the lesions of Iranian SED patients.
Methods: 100 patients with SED were enrolled in the study. The patients were evaluated both clinically for the severity of SED and microscopically for the presence of the yeast Malassezia. Diagnosis of Malassezia was made after the yeast Malassezia was microscopically observed on skin scales stained with methylene blue. All samples were also cultivated on Leeming and Notman and Sabouraud’s dextrose agar culture media. The agar plates were incubated at 32°C for 2 weeks and evaluated for the existence of growth every day for one week. Identification of isolated yeast was based on morphological and physiological characteristics.
Results: From 100 patients with SED, 60% were female. The age range was 12-65 years with median 27.3 years. The highest prevalence of SED was seen in 20-29 years age group. 59% and 41% of patients had local and generalized lesions, respectively. 58% of patients showed lesion on scalp. Microscopic examination of skin scales was positive in 100% of SED lesions. 96% of patients showed more than 1-3 yeasts in each microscopic field whereas only 4% patients showed 1-3 yeasts in whole slide. Totally, 77% of the specimens yielded Malassezia in culture. Malassezia globosa was the most commonly isolated Malassezia species (55.8%). Malassezia globosa had also most frequencies on scalp and face lesions. Malassezia furfur had most frequency on trunk lesions.
Conclusion: The results of our study showed high recovery rate of Malassezia species on lesions of patients with SED. So it might be playing a causative role in the etiology of this disease.

Corresponding Author: Mohammad T. Hedayati, PhD; e-mail: hedayaty2001@yahoo.co.uk

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