title: Quantitative skin cultures of Pityrosporum yeasts in patients seropositive for the human immunodeficiency virus with and without seborrheic dermatitis.
abstract: BACKGROUND
  Previous studies have suggested that Pityrosporum yeasts may be important in the pathogenesis of seborrheic dermatitis (SD). SD occurs more frequently and has a different clinical appearance in patients who are human immunodeficiency virus (HIV)-seropositive than in HIV-seronegative patients.
  
  
  OBJECTIVE
  Our purpose was to investigate the role of Pityrosporum yeasts in the pathogenesis of seborrheic dermatitis in HIV-seropositive patients.
  
  
  METHODS
  Twenty-eight HIV-seropositive patients, including seven patients with SD and 21 without SD, and 20 HIV-seronegative patients with SD (n = 10) and without SD (n = 10) were investigated. Quantitative Pityrosporum cultures were taken from the face, chest, and back.
  
  
  RESULTS
  None or only a small amount of Pityrosporum yeasts were cultured from SD lesions and SD predilection sites in HIV-seropositive patients. From the SD lesions in the HIV-seronegative control group large amounts of Pityrosporum yeasts were cultured.
  
  
  CONCLUSIONS
  The results of this and other studies suggest that Pityrosporum yeasts play no role in SD in HIV-seropositive patients and that SD in these patients is a distinct entity to be separated from "classical" SD in HIV-seronegative patients.
authors.affiliation: Department of Dermatology, Free University Hospital, Amsterdam, The Netherlands.
authors.forename: J R
authors.initials: JR
authors.lastname: Wikler
authors.forename: C
authors.initials: C
authors.lastname: Nieboer
authors.forename: R
authors.initials: R
authors.lastname: Willemze
mesh_terms: D000328:Adult; D012628:Dermatitis, Seborrheic / Q000150:complications / Q000382:microbiology*; D005260:Female; D006679:HIV Seropositivity / Q000150:complications / Q000382:microbiology*; D006801:Humans; D008290:Malassezia / Q000302:isolation & purification*; D008297:Male; D008875:Middle Aged; D012867:Skin / Q000382:microbiology*