Folliculitis decalvans and lichen planopilaris phenotypic spectrum: a case series of biphasic clinical presentation and theories on pathogenesis

Abstract

We present a series of 13 patients with clinical and histological features of both folliculitis decalvans (FD) and lichen planopilaris (LPP), either concomitantly, or sequentially as the clinical phenotype changed over time. This biphasic presentation of FD-LPP is not as uncommon as would be expected from the lack of description in the literature. We discuss current theories about the pathogenesis of both LPP and FD, and speculate how abnormal immune responses may either predispose to secondary bacterial infection or be influenced by dysbiosis of the skin/hair follicle microbiome, resulting in inflammation and permanent hair follicle damage.

Folliculitis decalvans and lichen planopilaris phenotypic spectrum: case report of two paediatric cases

“…Although an association of the two diseases continues to be debated in the literature. [3][4][5][6] a challenge is to distinguish vitiligo from the occurrence of hypopigmentation in areas of previously affected psoriatic skin. 7 The significant association with other autoimmune disorders reflects the common susceptibility genes identified in vitiligo and psoriasis, with allelic variations in key genes related to the immune response, such as autoimmune susceptibility 1 (AIS1; PSOR7).…”

“…[2][3][4] Recently, a FD/LPP phenotypic spectrum (FDLPPPS), combining clinical, trichoscopic and histopathologic features of both diseases was described in 20 adults. 5,6 Herein, we report the first two cases of FDLPPPS in children.…”

“…Nevertheless, as occurred in these cases, they can show concomitant clinical and histopathological features. 6,9 Tufting, pustules and yellow crusts are clinically characteristic of FD, whereas perifollicular cast and erythema suggest LPP. 5,9,10 Regarding histopathology, the identification of multicompound follicular structures, atrophy of the follicular epithelium and prominent plasma cell component instead of the predominance of neutrophils should be considered for the diagnosis of FDLPPPS.…”

A niche in the spotlight: Could external factors critically disturb hair follicle homeostasis and contribute to inflammatory hair follicle diseases?

“…[63,64] In the neutrophilic scarring alopecia folliculitis decalvans, biofilm formation along the hair follicle and the abnormal subepidermal microbiota is acknowledged as critical factors for the chronic persistence and recurrent flare-ups of this type of alopecia. [65] Interestingly, presence of Staphylococcus aureus in scalp skin of folliculitis decalvans patients increased the chance of subepidermal colonization, [66,67] pointing towards the possibility of translocation of bacteria across inflamed skin barriers.…”

Comment on: folliculitis decalvans and lichen planopilaris phenotypic spectrum: a case report of two paediatric cases

“…FD-LPP phenotypic spectrum is characterized as bi-phasic presentation of FD and LPP, which the original authors of the condition duly recognized not to be as uncommon as would be expected from the relative paucity of respective reports in the literature. 2 The most common clinical presentation is that of a scarring alopecia of the vertex with the loss of follicular ostia, perifollicular scaling, hair tufting and mixed histologic features of late FD and of LPP, including multicompound follicular structures, atrophy of the follicular epithelium, a lymphohistiocytic infiltrate with granuloma formation and prominent plasma cells, but usually the absence of a neutrophilic infiltrate. 3 In one study, 50% of lesional bacteria culture samples were positive for Staphylococcus aureus.…”