Abstract

45-year-old female presented with a well-circumscribed large alopecic patch on the crown and vertex of the scalp concerning for alopecia areata, but scalp biopsy was performed for further evaluation.  Histopathology revealed nearly all hair follicles to be in a state of miniaturization or telogen phase in the deeper levels. However, on additional level sections higher in the dermis near the isthmus and infundibulum of the hair follicles, aggregates of inflammation were seen which demonstrated vacuolar interface changes with the follicular epithelium, in addition to follicular plugging, mucin deposition and basement membrane thickening, all consistent with cutaneous lupus erythematosus. Surrounding the inflamed follicular infundibula, there was moderately dense perifollicular chronic inflammation, containing predominantly lymphocytes but also a few plasma cells.  Foci of perivascular, peri-eccrine, and perifollicular lymphoplasmacytic inflammation were found in the mid and deep dermis, with increased mucin at all levels of the dermis.  This case is one of discoid lupus erythematosus (DLE) with prominent follicular miniaturization mimicking alopecia areata.  It highlights the need for a high degree of suspicion clinically and the need for multiple level sections on histopathology to fully view the entirety of the folliculosebaceous unit to not miss key histopathologic findings.  As treatment and prognosis are vastly different for the two conditions, dermatologists need to be familiar with this presentation of DLE.