Identification of Malassezia species isolated from scalp skin of patients with psoriasis and healthy subjects.
The role of Malassezia species in psoriasis is still undetermined, but several reports have associated these lipophilic yeasts with the development of skin lesions in psoriasis. The aim of our study was to analyze the prevalence of Malassezia species in the scalp lesions of patients with psoriasis and assess the distribution of the species according to patient sex, age, and duration of the disease. Forty psoriatic patients with scalp involvement and the same number of clinically healthy individuals were included in the study. The samples were obtained by scraping the skin surface of the scalp of all subjects and then incubated on modified Dixon agar. The yeasts isolated were identified by their morphological and physiological properties according to Guillot et al method. M.globosa in its yeast phase was a predominant species (55%), followed by M.slooffiae (18%) and M.restricta (10%), the latter being the most common species isolated from healthy scalp skin. We found significant difference in the distribution of Malassezia species between psoriatic and healthy scalp skin and in the distribution of Malassezia species according to the severity of the scalp involvement.