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February 1990

Skin Surface Electron Microscopy in Pityrosporum Folliculitis: The Role of Follicular Occlusion in Disease and the Response to Oral Ketoconazole

Author Affiliations

From the Departments of Microbiology and Public Health Laboratory (Drs Hill and Rodgers and Ms Crowley) and Dermatology (Drs Goodfield and Saihan), University Hospital, Queen's Medical Centre, Nottingham, England. Dr Goodfield is now with the Department of Dermatology, General Infirmary Leeds (England), and Dr Rodgers is with the Department of Microbiology, Spaulding Life Science Center, University of New Hampshire, Durham.

Arch Dermatol. 1990;126(2):181-184. doi:10.1001/archderm.1990.01670260051009

† The yeast Pityrosporum orbiculare is thought to cause the folliculitis associated with seborrheic eczema. However, a combination of mechanical and microbiological factors may be involved, with follicular occlusion leading to yeast overgrowth and folliculitis. Scanning electron microscopy was used to investigate this hypothesis. Skin biopsy specimens obtained from patients with Pityrosporum folliculitis were examined by scanning electron microscopy before and after oral ketoconazole therapy. Patients with active disease showed occlusion of noninflamed follicles, which resolved after ketoconazole treatment. Follicular occlusion was not present in biopsy specimens obtained from unaffected controls nor was it related to the presence of P orbiculare. These findings suggest that follicular occlusion may be a primary event in the development of this folliculitis, with yeast overgrowth a secondary occurrence. The beneficial effect of ketoconazole in this disease may be due to direct effects on the follicle.

(Arch Dermatol. 1990;126:181-184)

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