Malassezia spp Carriage in Patients with Seborrheic Dermatitis

Abstract

The role of Malassezia spp in seborrheic dermatitis (SD) is controversial. To compare the cutaneous density and the cultural characteristics of Malassezia in persons with or without SD, quantitative cultures were obtained by stripping the forehead with a tape placed on Leeming and Notman medium. Plates were incubated at 37 degrees C in a plastic bag, and colonies were counted after 14 days. High yeast density was defined as > 100 colony forming units (CFU)/tape. Volunteers were divided into four groups depending on their HIV serology [HIV (+) versus HIV (-) or unknown] and their clinical status (with or without SD). 126/129 cultures were positive (97.7%). Malassezia spp density was low on clinically normal skin in all HIV (-) persons (40/40) but was high in 8/34 (24%) HIV (+) persons without SD (p < 0.001). In SD patients, high densities were found in 10/22 (45%) HIV (+) and in 17/33 (52%) HIV (-) persons. The strains could be divided into three basic groups on the basis of their cultural characteristics. Colony morphology type A predominated on normal skin (72%), and morphology type C predominated on persons with SD (78%). High yeast density can be present without skin symptoms. The pathogenicity of Malassezia seems more likely to be determined by the subtype present on the skin rather than by its density.

Epidemiologic Study ofMalasseziaYeasts in Patients withMalasseziaFolliculitis by 26S rDNA PCR-RFLP Analysis

“…These conditions include high temperature, high humidity and internal factors such as the long-term use of corticosteroids and immunosuppressants, chemotherapeutic agents, bone marrow transplantation, AIDS, leukemia and diabetes, which elicit the overgrowth of otherwise harmless Malassezia yeasts 1,2,18 . According to the previous studies, M. globosa is commonly isolated in pityriasis versicolor [19][20][21][22] , and although the reports on seborrheic dermatitis have varied [22][23][24] 26 , which stated that M. restricta was found in 4 cases (20%), M. globosa was found in 2 cases (10%) and M. furfur was found in 1 case (5%) on the face, while M. globosa was only predominant with a total of 12 cases (65%) on the neck, chest, flank and sacral area. These disparities may be attributable to the difference in the methods of the two studies, i.e., morphological analysis, such as the size, surface contour, color and shape of the Malassezia colonies, and molecular analysis, such as PCR and RFLP.…”

The Tape-Stripping Technique as a Method for Drug Quantification in Skin

“…Similarly, TS is performed to induce a defined disruption of the water barrier, e.g., to evaluate the effect of a subsequently applied skin care product in barrier restoration [50]. It may be also used to obtain cells for mycological culture [51,52] or to investigate SC quality [53]. In dermatopharmacology, the SC barrier function [50,54] and the bioavailability and bioequivalence of topical drugs [39,[55][56][57] can be evaluated with the use of this technique [58,59].…”

Caracterización de especies del género Malassezia en pacientes con dermitis seborreica y en controles

“…En relación a las especies identificadas (Tabla 3), los hallazgos coinciden en gran parte con los de Makimura 39 , quien encontró M furfur en pacientes con DS, pitiriasis versicolor y dermitis atópica; encontró M sympodialis en pacientes con las mis- Algunos autores 40 plantean que una alta densidad de levaduras puede presentarse sin lesiones de piel, situación que nosotros encontramos en 5% de los controles (Tabla 2) y postulan que la patogenicidad de Malassezia podría estar más relacionada con la especie involucrada que con su densidad. En nuestro trabajo, de las 8 especies identificadas en DS severa, 4 correspondieron a M globosa, 1 a M sympodialis y 3 a M furfur sensu stricto.…”