Epidermal psoriasiform hyperplasia, an unrecognized sign of folliculitis decalvans: A histological study of 26 patients

Abstract

Epidermal hyperplasia, sometimes psoriasiform and follicular microcysts, are significant histological signs of FD, which have been ignored until now although they seem very common.

Linear circumscribed scleroderma-like folliculitis decalvans: Yet another face of a protean condition

“…In a retrospective histological analysis of 26 patients with FD, the authors found follicular hyperkeratosis in 77%, hyperplasia of the interfollicular epidermis in 92% with a psoriasiform aspect in 88%, plasma cells in infiltrate in 92%, in 42% in large quantities, and hair tufting in 54%. [ 31 ]…”

Epidermal thickness is useful in distinguishing lichen planopilaris from neutrophil‐poor/lymphocyte‐predominant folliculitis decalvans

“…Still, this clue may be absent, and there is a need for additional tools to help make a diagnostic distinction between LPP and neutrophil‐poor FD. Recently, previously unrecognized epidermal hyperplasia in FD was described and measured, thereby providing a new histopathologic criterion to diagnose FD 1 . In that report, however, no comparison of the epidermal thickness in FD was made to LPP.…”

“…Likewise, LPP is classified as “lymphocytic.” However, advanced lesions of FD may be neutrophil‐poor, featuring mostly lymphocytes and plasma cells 3 . Neutrophil‐poor FD may also be termed “lymphocyte‐predominant.” In cases of neutrophil‐poor FD, a distinction from LPP may be challenging if not impossible 1,4,5 . One useful clue in distinguishing FD from LPP is the number of fused follicular infundibula in a compound follicle.…”

“…Lichen planopilaris (LPP) and folliculitis decalvans (FD) can, at times, be difficult to distinguish clinically as well as histopathologically from each other. 1 There are a small number of reported cases of FD-LPP overlap, 2 however, these cases are limited in number, and the most commonly used working classification of primary cicatricial alopecia remains the North American Hair Research Society (NAHRS) in which FD is categorized as a 'neutrophilic' primary cicatricial alopecia along with dissecting folliculitis/cellulitis. Likewise LPP is classified as 'lymphocytic.'…”

Inflammasome Activation Characterizes Lesional Skin of Folliculitis Decalvans

“…Understandably, the result is reduced self-esteem and psychological effects impacting patients' quality of life (4). Histological findings include a dense perifollicular neutrophilic infiltrate, affecting the upper and middle part of the follicle in the acute phase of the disease, evolving to a lympho-plasmocytic nature extending to the advential dermis, with psoriasi-form epidermal hyperplasia, deep follicular microcysts, polytrichia, disappearance of the sebaceous glands and dermal fibrosis in the late-stage (1,5).…”