Distribution ofMalasseziaspecies in seborrhoeic dermatitis: correlation with patients’ cellular immune status

Abstract

Malassezia species are implicated in the pathogenesis of seborrhoeic dermatitis (SD), but the relationship between each species and the disorder remains unclear. It is hypothesised that the pathogenesis of SD has an immune component, which is supported by the increased incidence in patients with immunosuppressive disorders. The purpose of our study was to analyse the prevalence of Malassezia species in lesional skin of SD, and to assess the distribution of the species according to severity of the disease and cellular immune status of the patients. Forty SD patients with scalp involvement were included in the study. The samples were obtained by scraping the skin surface of the scalp and then incubated on Sabouraud dextrose agar and modified Dixon agar. The yeasts isolated were identified by their morphological and physiological properties according to the method of Guillot et al. In addition, we performed two-colour flow cytometry analysis to investigate the lymphocyte subpopulations in the peripheral blood. The most commonly isolated species was Malassezia restricta (27.5%), followed by Malassezia globosa (17.5%) and Malassezia slooffiae (15%). We demonstrated low helper/suppressor ratios in 70% patients, because of an increase in the suppressor T-cell population, suggesting an impaired cellular immunity. However, we found no significant difference in the distribution of isolated Malassezia species according to the severity of the scalp involvement and changes in the peripheral blood lymphocyte subpopulations.

Distribution of Malassezia species in Mexican seborrheic dermatitis patients

“…a correlation was not found between the severity of SD and species distribution. This result is similar to the data obtained by Prohic (2010), in a study of 40 patients where the species identification was performed by chemical methods. The most commonly isolated fungi were M. restricta (27.5%), followed by M. globosa (17.5%) and M. slooffiae (15%).…”

“…In total, 42% had a family history of seborrheic dermatitis. Ninety-eight percent of patients reported trigger factors, such as stress/depression/fatigue (76%) and seasonal variation (44%) (Prohic, 2010;Dawson, 2007). In the present study, the majority (65%) of patients reported that stress was related to outbreaks.…”

Malassezia species in healthy skin and in dermatological conditions

“…Most of the studies published in recent years demonstrate geographical variations in the rates at which the various species are isolated, although a correlation between yeast density and severity of SD has been reported . However, in some reports, the quantity of yeasts was found not to be correlated positively with the severity of disease . In a culture‐based study, Gupta et al .…”

Seborrhoisches Ekzem

“…Prohic [8] wies eine erhöhte Anzahl an CD8 + -Zellen bei 60% der Patienten und eine erniedrigte CD4 + /CD8 + -Ratio nach, die annehmen lässt, dass Patienten mit seborrhoischem Ekzem eine beeinträchtigte zelluläre Immunität aufweisen. Eine erhöhte Produktion von IgG-Antikörpern wurde von verschiedenen Autoren beobachtet, wobei diese nicht gegen Hefen gerichtet sind.…”

“…Wahrscheinlich wegen unterschiedlicher Probengewinnungs-und Differenzierungsmethoden und ethnischen und/oder geografischen Besonderheiten weist die Verteilung der Malassezia-Spezien auf dem Körper erhebliche Unterschiede auf. Manche Autoren wiesen M. globosa als häufigste Spezies aus, andere M. sympodialis oder M. restricta[8]. Ob die Besiedlungsdichte der Malassezia-Hefen bei Patienten mit seborrhoischem Ekzem erhöht ist, bleibt allerdings unklar, obwohl manche Autoren eine Korrelation zwischen der Hefendichte und der Schwere des seborrhoischen Ekzems beobachteten.…”