Track

Clinical Studies

Abstract

Subtle, diffuse lichen planopilaris (LPP), including the frontal fibrosing variant (FFA) can be difficult to distinguish from female pattern hair loss (FPHL), especially when there is superimposed seborrheic dermatitis. No publication has compared the presence of colonizing yeast (Malassezia species) in the scalp among these three diseases. We have observed that colonizing yeast is rarely identified in LPP/FFA while it is commonly present in FPHL, and, therefore, we performed a cross-sectional, observational study to confirm these observations.

We compared the presence of yeast from biopsies with definitive diagnoses of FPHL, LPP, and FFA using a PAS-D stain. There were 137 biopsies collected over the span of 2 years consisting of 68 FPHL, 34 LPP, and 35 FFA specimens (Average age 60.16 years; all patients female). A single 4mm archival biopsy, processed with transverse/horizontal sections, was analyzed for each patient.

The study confirms a distinct difference in the presence of yeast between FPHL and LPP/FFA. In FPHL, 50% (34/68) of the cases had identifiable yeast. In FFA, only 3% (1/35) of the cases had identifiable yeast. In LPP, 0% (0/34) had identifiable yeast.

This study confirms a distinct difference in the presence of colonizing yeast between FPHL and LPP/FFA. LPP/FFA almost never has colonizing yeast, likely the result of pathologic loss of sebaceous glands, which provide an oil-rich environment in which yeast can survive. Importantly, the study confirms that identifiable yeast is a useful histopathologic clue to distinguish subtle LPP/FFA from FPHL.