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.

CONCLUSION:

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.