Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 5 3 2013 09 15 268 271 EN Ali Zarei-Mahmoudabadi Department of Medical Mycology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran AND Infectious and Tropical Diseases Research Centre, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Majid Zarrin Department of Medical Mycology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Forough Mehdinezhad Department of Medical Mycology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. 2015 10 16 Background and Objective: Seborrheic dermatitis (SD) is a frequent disorder of the skin that is distinguished by the development of erythematous patches and yellow-gray scales. It is a multifactor disease that requires predisposing factors for its progress. Presence of these factors leads to reproduction of opportunistic yeast Malassezia spp.The aim of the present study was to isolate and identify distribution of Malassezia species on the scalp of SD patients in Ahvaz using modified Dixons agar. Materials and Methods: A total of 110 patients diagnosed with SD were sampled. The sampling was carried out by brushing the hair and collecting the dandruff in paper pockets. For identification of Malassezia species, the scalp scales were cultured in Dixons agar. A combination of different characteristics including yeast cell morphology, ability to grow on Sabouraud dextrose agar, catalase test and ability to utilize individual Tweens (20, 40, 60 & 80) were used for identification of species. Results: Twenty-seven of 110 (24.5%) SD patients had positive cultures for Malassezia species of which 17 (63%) were male and 10 (37%) were female. The most commonly identified Malassezia species was M. globosa (40.7%) followed by M. pachydermatis (22.2%), M. furfur (11.1%) and M. restricta(7.4%) and Malassezia species (18.5%). Conclusion: Malassezia globosa was considered to be the most important orgaism involved in cases with Seborrheic dermatitisin this study. https://ijm.tums.ac.ir/index.php/ijm/article/view/575 https://ijm.tums.ac.ir/index.php/ijm/article/download/575/349