DermatopathologyA histologic review of 27 patients with lichen planopilaris
Introduction
Cicatricial alopecias are a group of disorders in which follicular units are replaced by fibrous tissue, resulting in progressive and permanent scarring hair loss.1 Several underlying disease processes may eventuate in scarring alopecia. These underlying diseases may be diagnosed both clinically and histologically in their early stages; however, in late stages only nonspecific scarring is evident.2
Key diagnostic features present in all forms of cicatricial alopecia include both visual loss of follicular ostia and destruction of the hair follicles and sebaceous glands on histopathologic examination. This can result from primary processes in which inflammation is directly targeted at the hair follicle or from secondary processes in which follicular destruction results from an inflammatory process that secondarily extends to the hair follicle, resulting in its destruction.3, 4
According to the North American Hair Research Society (NAHRS), the primary cicatricial alopecias are categorized according to the predominant inflammatory cell type: lymphocytic, neutrophilic, or mixed infiltrates. The lymphocytic group consists of chronic cutaneous lupus erythematosus, classic pseudopelade (Brocq), lichen planopilaris (LPP), central centrifugal cicatricial alopecia, alopecia mucinosa, and keratosis follicularis spinulosa decalvans. The neutrophilic group is comprised of folliculitis decalvans and dissecting cellulitis. Folliculitis (acne) keloidalis, folliculitis (acne) necrotica, and erosive pustular dermatosis are characterized by a mixed inflammatory infiltrate consisting of lymphocytes, plasma cells, and/or neutrophils5 (Table I).
Historically, LPP was first described by Pringle in 1895 as classic lichen planus in conjunction with spinous follicular papules.6, 7 Terminology including “follicular lichen planus of the scalp” and “folliculitis decalvans et atrophicus” has been employed in the previous literature.8 LPP can be subdivided into 3 variants: classic LPP, frontal fibrosing alopecia, and Graham-Little syndrome.9 LPP is seen most often in adults and, in contrast to lichen planus, it more commonly affects women.7 The mean age at onset is 52 years.7 The clinical course is chronic and progressive.
The clinical hallmark of active disease is the presence of erythematous or violaceous papules associated with perifollicular collarettes of scale4, 8, 10, 11 and a positive pull test for anagen hairs.12 Disease activity is greater at the periphery of the alopecic patch, which contrasts with the predominantly central activity seen with discoid lupus erythematosus (DLE).3, 13 Associated symptoms include moderate to severe scalp pruritus and dysesthesia (pain, discomfort, and burning). Lesions are classically multifocal and may eventually merge to produce large areas of hair loss.14 Smooth bare hypopigmented patches lacking follicular ostia characterize the chronic end stages.12 Other common presenting symptoms include hair loss and scalp tenderness.10 Sites of predilection are the frontocentral scalp and crown.15 Typical lichen planus involving nonfollicular skin, nails, and mucous membranes is seen in 50% of cases8 (Table II).
Cicatricial alopecias are considered a trichologic emergency. Early diagnosis and institution of treatment are paramount and can prevent permanent hair loss. Clinical features of LPP often overlap with those of other cicatricial alopecias, necessitating histologic evaluation in order to arrive at the correct diagnosis. There are certain histologic features that are unique to LPP. The purpose of this study was to examine biopsy specimens of known cases of LPP to identify the key histologic features that characterize this entity, such that an earlier and accurate diagnosis can be made with the ultimate goal of improving patient outcomes.
Although transverse (horizontal) sections are recommended and preferred by some investigators for evaluation of alopecias histologically since they allow visualization of as many follicular units as possible and at multiple levels,5, 16 a recent study found vertical sections to be superior to transverse sections alone.17 Vertical sections have the advantage of providing visualization of the overall reaction pattern and of the superficial dermis and dermoepidermal junction. Vertical sections are used at our institution for technical reasons and because of the preferences of our dermatopathologists. They typically provide sufficient histologic detail that, together with appropriate clinical correlation, allows accurate diagnosis.
Section snippets
Methods
A retrospective review of patients' medical records and pathology reports was conducted after receiving Institutional Review Board approval. Five separate searches of the pathology database were conducted for cases seen between 1992 and 2003. To be included in the study, patients had to be seen at least once by a Cleveland Clinic physician with at least one biopsy specimen taken of the lesion in question. Search terms included (1) alopecia not otherwise specified, (2) lupus, (3) inflammatory
Clinical findings
In this study, 20 patients were retrospectively diagnosed as having classic LPP, one as having frontal fibrosing alopecia, and 8 were labeled as “nonspecific” because they did not fit into a single category of LPP. Common findings included follicular hyperkeratosis, pruritus, scalp pain, and perifollicular erythema. The majority of patients had patchy hair loss on the parietal scalp and experienced a 51% to 75% extent of disease in that area. Associated lichen planus was present in 8 cases; it
Discussion
Because of the symptomatic nature of the condition and the enlarging areas of permanent alopecia, which are difficult to camouflage, patients with LPP frequently have disturbances in psychosocial interactions and self-perception.20 Immediate and aggressive therapy that reduces the inflammation and protects the follicle and sebaceous glands from destruction is needed if the hair follicle is to survive the inflammatory assault. The goal of this clinicopathologic review is to delineate the
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2020, Diagnostic HistopathologyCitation Excerpt :The use of PAS will also help to identify subtle basement membrane zone thickening in the evaluation of lupus. Elastic stains are invaluable in assessing subtle perifollicular fibrosis and highlighting fibrous tracts,24–26 as well as mucin stains for distinguishing the mucinous perifollicular early fibroplasia in scarring LPP27 or highlighting the interstitial dermal mucin diagnostic of lupus.21,28,29 Sebaceous gland atrophy of the scalp was originally reported by Headington et al. in 1989 in association with psoriasis.30
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2018, JAAD Case ReportsCitation Excerpt :Conversely, in CCCA the area that is first to be affected is the central scalp, after which it starts expanding centrifugally.8 Histopathologic features are overlapping between CCCA and LPP.8,15 It is noteworthy that the isolated involvement of the temporal area—the site at which the hair has been under large amounts of strain in our patient—further supports that traction was the triggering factor of LPP.
Funding sources: None.
Conflicts of interest: None declared.
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Ms Tandon and Dr Somani share first authorship of this article.