HIV disease and Malassezia yeasts: a quantitative study of patients presenting with seborrhoeic dermatitis.

Seborrhoeic dermatitis (SD) is a disease that affects 1-3% of the general population, 3-5% of young adults and 20-83% of patients with AIDS. Malassezia yeasts have been associated with the pathogenesis of this condition. The association between the Malassezia yeasts and HIV-related SD is still a controversial subject. The objective of our study was to investigate the role of Malassezia yeasts in the pathogenesis of SD in the HIV population comparing the number of yeasts' cells with the severity of the disease and degree of immunosuppression. We used two quantitative counting methods: direct counting with Sellotape-stripped skin and recovery of the yeasts in culture using contact plates. This investigation has demonstrated that there is a trend between numbers of yeasts present on lesional skin, severity of SD and CD4-positive T lymphocytes count in HIV-positive patients. No quantitative differences were observed between HIV-related and non-HIV related SD.