Prepubertal Fibrosing Alopecia in a Pattern Distribution

ABSTRACT

Fibrosing alopecia in a pattern distribution (FAPD) is a cicatricial alopecia characterized by an androgenetic alopecia (AGA)-like pattern hair loss (PHL) associated with a lichen planopilaris (LPP)-like infiltrate on histopathology. Prepubertal PHL is the term proposed for AGA in children. The pattern is exclusively that of female PHL. We report the first case of FAPD in a child with prepubertal PHL. A 9-year-old girl initially presented with chronic itching, redness, and scaling of the central scalp area, which eventually developed to a cicatricial PHL with histopathological evidence of LPP. The implication of a follicular microinflammation and fibrosis associated with AGA has emerged from several studies. Ultimately, Zinkernagel and Trüeb reported a peculiar cicatricial PHL with histopathological features of LPP and named it FAPD. So far, FAPD has only been observed in adults. The observation of FAPD in a child with prepubertal PHL suggests that the condition is not androgen dependent and may explain the limited efficacy of 5-alpha reductase inhibitors for treatment of FAPD. The primary aims for treatment are anti-inflammatory in combination with a hair growth-promoting agent such as minoxidil.

INTRODUCTION

Patterned hair loss (PHL) or androgenetic alopecia (AGA) is generally understood to represent a hereditary and androgen-sensitive, progressive thinning of the scalp hair with sex-dependent differences in frequency, age of onset, and pattern of alopecia. While the male pattern, as originally classified by Hamilton and Norwood,[1,2] is characterized by its typical symmetrical bitemporal or frontal recession of the hairline and balding vertex, the female pattern, as later reported by Ludwig,[3] is set apart by a more diffuse thinning of the crown area, while the frontal hair line remains intact.

Prepubertal PHL is the term originally proposed by Trüeb et al.[4] on the basis of earlier reports of smaller case numbers[5] and a retrospective chart review of the clinical features and natural progression of pediatric patients under the age of 10 with a diagnosis of AGA seen at a referral center during a 10-year period, with a total number of 74 (59 female and 15 male). The clinical presentation was exclusively that of thinning of the hair and widening of the central parting of the scalp consistent with the pattern of AGA of the female PHL (FPHL) type. Normal development and no endocrinological abnormalities are usually the case. The authors made the point that the observation of PHL in prepubertal children and its clinical presentation pattern suggests that FPHL may not be necessarily androgen dependent.

Zinkernagel and Trüeb originally reported a peculiar type of cicatricial PHL with histopathological features consistent with lichen planopilaris (LPP) and named it fibrosing alopecia in a pattern distribution (FAPD).[6] In the, so far, most comprehensive review of a total of 15 articles describing FAPD in a total of 188 patients (164 women and 24 men; average age = 53.8), an average age of 53.8 years with ages ranging from 21 to 82 years in women and 24 to 73 years in men was found.[6] So far, FAPD has not been reported in children.[7]

CASE REPORT

An otherwise healthy girl presented with persistent itching, redness, and scaling of the central scalp [Figure 1] since the age of 9 years, which was initially treated as seborrheic dermatitis, only later to be recognized to be cicatricial PHL with the respective progressive thinning of hair in the centroparietal scalp area associated with histopathologic evidence of an LPP-like inflammation. There was a strong family history for PHL.

Figure 1.

Widening of the lateral hair part with diversity of hair shaft diameters, perifollicular erythema, fine scaling, and evidence of follicular dropout

Scalp dermoscopy revealed a significant diversity of hair shaft diameters associated with perifollicular erythema, scaling, and scarring as evidenced by selective dropout of hair follicles.

Due to treatment resistance to antiseborrheic treatment, a biopsy of the parietal area was performed and showed a moderate lymphocytic infiltrate at the level of the follicular isthmus associated with lamellar perifollicular fibrosis and selective dropout of hair follicles [Figure 2a and b].

Figure 2.

(a and b) Histopathology: (a) Hematoxylin–eosin staining: Moderate lymphocytic infiltrates and lamellar fibrosis at the level of the isthmus, and selective dropout of hair follicles. (b) Elastin staining: selective dropout of hair follicles as evidenced by the focal collapse of elastin fibers (arrows). Dermatopathology Laboratory, University of Hospital of Zurich, Department of Dermatology, H2017.3899

Treatment was successfully initiated with a topical compound of 5% minoxidil and 0.2% triamcinolone acetonide once daily and later switched to 0.625 mg oral minoxidil in combination with a propylene glycol-free, North American witch-hazel (Hamamelis virginiana)-based solution of 5% minoxidil sulfate for maintenance.[8]

DISCUSSION

We report the first case of FAPD with onset in a prepubertal child, characterized by the typical female pattern of alopecia associated with the histopathological features of LPP.

An important question to be raised is how the lichenoid tissue reaction pattern is generated around the individual hair follicle. Follicles with some form of damage or malfunction might express cytokine profiles that attract inflammatory cells to assist in damage repair or in the initiation of apoptosis-mediated organ deletion. Alternatively, an as yet unknown antigenic stimulus from the damaged or malfunctioning hair follicle might initiate a lichenoid tissue reaction in the immunogenetically susceptible individual. Remarkably, in healthy murine skin, cluster of perifollicular macrophages have been described as perhaps indicating the existence of a physiological program of immunologically controlled hair follicle degeneration by which malfunctioning follicles are removed by programmed organ deletion.[9] With regard to its pathogenesis, LPP is regarded to be a T-cell-mediated autoimmune reaction that triggers apoptosis of the follicular epithelial cells. This autoimmune process is thought to be in response to some antigenic challenge, but a specific antigen has yet not been identified. Harries et al. provide the first evidence that LPP may result from an immune privilege collapse of the hair follicle’s epithelial stem cell niche.[10] Where a causal or triggering agent is identified, this is termed a lichenoid reaction rather than lichen planus. This may include drug reactions, viral hepatitis, and cutaneous graft-versus-host disease (GvHD).

GvHD is a common complication following allogeneic tissue transplantation and is induced and maintained by immunocompetent cells from the donor tissue (graft) that particularly attack epithelia of fast-proliferating tissues of the recipient (host), such as those from the gastrointestinal tract, liver, and the skin. The skin is the most common organ involved. While the cutaneous, mucosal, and nail manifestations of chronic GvHD are well recognized, involvement of the hair follicle has so far found lesser attention. Due to its analogies with lichen planus, GvHD constitutes a model that may lead to a better understanding of the pathophysiological features of lichen planus and LPP. Notably, chronic GvHD may present on the scalp as FAPD.[11]

In their original report, Zinkernagel and Trüeb suggested that oral 5-alpha reductase inhibitors may be an effective for treatment of FAPD by virtue of their specific effect on the androgenetic hair follicle.[6] However, clinical experience has shown a limited efficacy of the 5-alpha reductase inhibitors for treatment of FAPD. The observation of prepubertal FAPD suggests that the condition may not be androgen dependent and would explain the limited efficacy of 5-alpha reductase inhibitors. By definition, the pediatric age group is <18 years and thus includes adolescents with the respective endocrine particularities, while prepubertal children represent a more homogeneous population of children before the rise of sexual hormone levels. On average, girls begin puberty at ages 10–11 and complete puberty at ages 15–17; boys generally begin puberty at ages 11–12 and complete puberty at ages 16–17.

Prepubertal PHL and prepubertal FAPD share the prepubertal onset, absence of endocrinological abnormalities, are androgen independent, and persist into adulthood while being amenable to treatment. The primary aims for treatment are primarily anti-inflammatory in combination with a hair growth-promoting agent such as minoxidil.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Conflicts of interest

This work represents an integral part of Nikollas Munhoz’s trichology traineeship at the Center for Dermatology and Hair Diseases Professor Trüeb.

Funding Statement

Nil.