Scalp Biopsy Specimens Research Articles

Profibrotic Subsets of SPP1+ Macrophages and POSTN+ Fibroblasts Contribute to Fibrotic Scarring in Acne Keloidalis

Acne keloidalis is a primary scarring alopecia characterized by longstanding inflammation in the scalp causing keloid-like scar formation and hair loss. Histologically, acne keloidalis is characterized by mixed leukocytic infiltrates in the acute stage followed by a granulomatous reaction and extensive fibrosis in the later stages. To further explore its pathogenesis, bulk RNA sequencing, single-cell RNA sequencing, and spatial transcriptomics were applied to occipital scalp biopsy specimens of lesional and adjacent no-lesional skin in patients with clinically active disease. Unbiased clustering revealed 19 distinct cell populations, including 2 notable populations: POSTN+ fibroblasts with enriched extracellular matrix signatures and SPP1+ myeloid cells with an M2 macrophage phenotype. Cell communication analyses indicated that fibroblasts and myeloid cells communicated by SPP1 signaling networks in lesional skin. A reverse transcriptomics in silico approach identified corticosteroids as possessing the capability to reverse the gene expression signatures of SPP1+ myeloid cells and POSTN+ fibroblasts. Intralesional corticosteroid injection greatly reduced SPP1 and POSTN gene expression as well as acne keloidalis disease activity. Spatial transcriptomics and immunofluorescence staining verified microanatomic specificity of SPP1+ myeloid cells and POSTN+ fibroblasts with disease activity. In summary, the communication between POSTN+ fibroblasts and SPP1+ myeloid cells by SPP1 axis may contribute to the pathogenesis of acne keloidalis.

A comparative study of histopathologic features in alopecia areata and pattern hair loss.

When peribulbar infiltrates are absent, other histopathologic findings are necessary to distinguish alopecia areata (AA) from pattern hair loss (PHL). The purpose of this study is to determine which histopathologic features are most useful for differentiation. A retrospective slide review was conducted of AA and PHL scalp biopsy specimens from 2014 to 2019 at a tertiary referral center. Ninety-six cases were retrieved, of which 38 were AA. Peribulbar infiltrates were identified in 24 AA (63.2%) cases. A catagen/telogen shift was observed more frequently in AA than PHL (25 cases, 65.5% vs. 10 cases, 17.2%; p ≤ 0.0001). Lymphocytes (4 cases, 10.5% vs. 1 case, 1.7%; p=0.058) and melanin (25 cases, 65.8% vs. 5 cases, 8.6%; p ≤ 0.0001) in fibrous tracts were more common in AA. Apoptotic bodies within vellus hairs were more frequently identified in AA (32 cases, 84.2% vs. 37 cases, 63.8%; p=0.030). Small dystrophic follicles were also more common in AA (16 cases, 42.1% vs. 1 case, 1.7%; p < 0.0001). Common features of AA other than peribulbar infiltrates include a catagen/telogen shift, melanin in fibrous tracts, and small dystrophic follicles. Practitioners should consider these features when distinguishing AA from PHL in specimens without peribulbar infiltrates. The retrospective design limits our ability to exclude multifactorial alopecia, such as telogen effluvium.

Histopathological Evidence of Occipital Involvement in Male Androgenetic Alopecia.

Background: The occipital region of the scalp is generally accepted as an unaffected area of androgenetic alopecia (AGA) for both genders. However, evidence of AGA involving the occipital scalp has been demonstrated in women; meanwhile, it is unclear whether occipital involvement also occurs in men.Objective: We aimed to determine if there is occipital involvement in men with AGA.Methods: This case-control study compared hair counts of scalp biopsy specimens from the occipital region of 82 men with Hamilton-Norwood III-VII and 82 unaffected men.Results: The mean ages of men with AGA and controls were 40.1 ± 8.9 and 38.6 ± 10.5 years, respectively (P = 0.291). A significant decrease in total hair follicles, terminal hair follicles, follicular units and terminal to vellus (T:V) ratio, along with a significant increase in follicular stelae was indicated in the AGA group compared to controls (all P < 0.05). Subgroup analyses revealed that average counts of total hair follicles, terminal hair follicles and T:V ratios were also significantly lower in males with Hamilton-Norwood VI and VII than in controls (all P < 0.05). There were no correlations between increasing age and hair count parameters, but a significant negative association was found between total follicle numbers and disease duration (r = −0.23, P = 0.02).Conclusions: AGA can involve the occipital area of male patients with advanced disease. Therefore, the occiput of particular cases should not be used to determine reference data for normal scalp hair, and preoperative measurements of miniaturized hairs in the donor site are strongly recommended in all persons undergoing hair transplantation.

The study of hair follicle counts from scalp histopathology in the Thai population.

The horizontal section of a scalp specimen offers an advantage over a vertical section by providing quantitative information. The reference data for hair counts in Asians, including Thais, are inconclusive. We aimed to determine the normal values of hair counts in scalp biopsy specimens in the Thai population. A 4-mm punch biopsy was performed at the occipital area of the scalp from subjects presenting with clinically normal hair and scalp appearance. All specimens were horizontally sectioned and observed to assess the number of follicular units and hair follicles, type of hairs, and phase of the hair cycle. The results were further compared between sexes and with the pre-existing data from previous studies. Ninety specimens were collected from 90 subjects. The average number of total hairs, terminal hairs, vellus hairs, and follicular units per 4-mm punch scalp skin were 20.5±5.2, 18.2±4.1, 2 (range 0-7), and 9.1±1.6, respectively. The mean ratio of terminal to vellus hair was 8.9:1 and of anagen to telogen hair was 91.9:7.9. There were no gender differences in any of the parameters and no correlations with changing age. Compared to other Asian populations, Thais and Taiwanese showed intermediate values between Iranians and Koreans; when compared to other ethnic groups, hair density in Asians showed lower than Caucasians and Hispanics but was comparable to Africans. This study established reference values of scalp horizontal sections in the Thai population; this will be helpful for clinicians and researchers to evaluate hair disorders.

Fibroproliferative genes are preferentially expressed in central centrifugal cicatricial alopecia

Central centrifugal cicatricial alopecia (CCCA) is a primary cicatricial alopecia that most commonly affects women of African descent. Like CCCA, fibroproliferative disorders (FPDs) such as keloids, atherosclerosis, and fibroids are characterized by low-grade inflammation and irritation, resulting in end-stage fibrosis. We sought to determine whether fibroproliferative genes were up-regulated in patients with CCCA. A total of 5 patients with biopsy-proven CCCA were recruited for this study. Two scalp biopsy specimens were obtained from each patient; 1 from CCCA-affected vertex scalp and 1 from the unaffected occipital scalp. Microarray analysis was performed to determine the differential gene expression patterns. There was an upregulation of genes implicated in FPDs in patients with CCCA. Specifically, we noted increased expression of platelet derived growth factor gene (PDGF), collagen I gene (COL I), collagen III gene (COL III), matrix metallopeptidase 1 gene (MMP1), matrix metallopeptidase 2 gene (MMP2), matrix metallopeptidase 7 gene (MMP7), and matrix metallopeptidase 9 gene (MMP9) in affected scalp compared with in unaffected scalp. Significant overlap in the canonic pathways was noted between patients with CCCA and patients with both atherosclerosis and hepatic fibrosis (P<.001). Small sample size and the use of whole skin tissue for analysis. We have identified the upregulation of critical genes implicated in FPDs in the gene expression profile of patients with CCCA. These findings may help identify future therapeutic targets for this otherwise difficult-to-treat condition.

Horizontal and vertical sections of scalp biopsy specimens from dermatomyositis patients with scalp involvement.

The histologic findings of scalp involvement in dermatomyositis are not well characterized on account of a lack of large series. To systematize the histologic features of scalp involvement in dermatomyositis on horizontal and vertical sections. A descriptive, prospective, cross-sectional study recruited 31 patients with pathologically and serologically confirmed dermatomyositis in Mexico City, Mexico, from June 2014 to June 2015. A total of 36 scalp biopsy specimens from 20 patients with scalp involvement in dermatomyositis were processed as 20 vertical and 16 horizontal sections. Dilated capillaries and diffuse mucin deposition were detected in all biopsy specimens, followed by interface dermatitis. Partial or segmental thickening of the basement membrane, hyperkeratosis, atrophic epidermis, and acrosyringeal hypergranulosis with hyperkeratosis were other very common findings. Preserved follicular architecture, with intact or slightly atrophic sebaceous glands, was present in most horizontal sections. There was decreased follicular density, with a terminal-to-vellus ratio of 4:1 and telogen count of 10.3%. Eosinophils were present in 15% and 25% of horizontal and vertical sections, respectively. No special stains performed. Scalp involvement in dermatomyositis shows nonscarring pattern on horizontal sections that is consistent with chronic telogen effluvium. Telangiectasia and mucin are universal histologic features; eosinophils and acrosyringeal hypergranulosis with hyperkeratosis are new findings.

Evaluation of Alopecia: A New Processing Technique Combining Vertical and Transverse Sections from a Single Scalp Biopsy Specimen.

Background:Histopathological study of alopecia generally requires both vertical and transverse sections (VS and TS) and this may demand the need for multiple scalp biopsy samples. Here, we suggest a new processing technique which provides both VS and TS from a single biopsy, thus making the interpretation easier.Materials and Methods:All formalin-fixed scalp biopsy specimens were processed routinely. Nine VS were taken and mounted on 3 glass slides. The block was then melted and the tissue reembedded with the subcutaneous tissue facing downward and the epidermal aspect toward the technician to obtain TSs. Serial 4 μ sections were cut until the tissue was exhausted and every 25th section was mounted on glass slides and stained with H and E.Results:100 scalp biopsy specimens with the history of alopecia have been processed using this technique. The technique provides proper visualization of both VS and TS from a single scalp biopsy without compromising the quality. Further, evaluation of the remaining sections with application of special stains can also be possible with this technique which will maximize the information and contribute to the accurate diagnosis of various types of alopecia.Conclusions:This technique can be used to obtain diagnostically satisfactory VS and TS from a single scalp biopsy specimen by modifying the embedding procedure, thereby avoiding the need for a second biopsy. All types of alopecia can be diagnosed by this effective method.

Presence of Mast Cells and Mast Cell Degranulation in Scalp Biopsies of Telogen Effluvium.

Background:Telogen effluvium (TE) is a type of acquired, diffuse alopecia that occurs due to an abnormal shift of scalp hair follicles from anagen to telogen, leading to premature shedding of hair. Previous studies have suggested the existence of a neuroimmunologic “brain-hair follicle” axis, in which mast cells have been implicated as an important link between the nervous system and immunologic system.Objective:The current study sought to investigate the role of mast cell presence and mast cell degranulation in the pathogenesis of TE.Materials and Methods:Mast cells were counted using Giemsa and tryptase immunohistochemical stains in scalp biopsy specimens with the pathologic diagnosis of TE (TE, n = 10), alopecia areata (AA, n = 7), and androgenic alopecia (ANDRO, n = 9).Results:We found significant (P < 0.001) group-level differences between the mean mast cell counts per high-power fields for each type of alopecia studied. Tukey post hoc analysis showed the mean mast cell count for TE to be significantly larger than AA for both Giemsa (P = 0.002) and tryptase (P = 0.006); significantly larger than ANDRO for both Giemsa (P < 0.001) and tryptase (P < 0.001); and significantly larger when compared to normal scalp skin for both Giemsa (P < 0.001) and tryptase (P < 0.001). No significant difference of mean mast cell counts was observed for AA compared to ANDRO for Giemsa (P = 0.373) or tryptase (P = 0.598) stains.Conclusion:Our findings suggest that mast cells could play a role in mediating stress-induced hair loss seen in TE.

Histopathologic diagnosis of multifactorial alopecia.

Establishing a definitive diagnosis for any form of alopecia can be challenging. Adding to the diagnostic complexity is the fact that many patients have more than one form of alopecia contributing to their hair loss. We conducted a review of 1360 consecutive scalp biopsy specimens submitted for the evaluation of scalp hair loss over a 16-month period, demonstrating that 12.5% of cases had a combination of diagnoses (multifactorial alopecia) accounting for their hair loss. An approach to the histopathologic diagnosis of multifactorial alopecia, particularly multiple forms of alopecia found in a single biopsy, is here presented.

A Comparison of Vertical and Transverse Sections in the Histological Diagnosis of Alopecia Areata Scalp Biopsy Specimens.

Context:Both vertical and transverse sections are used for the diagnosis of alopecia areata. However when a single biopsy is submitted the pathologist has to decide which type is better.Aims:To compare the diagnostic histological features in vertical and transverse sections in alopecia areata scalp biopsy specimens.Settings and Design:Tertiary Care Hospital. Comparative Study.Materials and Methods:A total of 30 patients were enrolled in the study. Two four mm punch biopsy were taken. One was used to take vertical sections and the other for transverse section and histological features of alopecia areata noted in both.Statistical Analysis Used:Chi-square test, percentage.Results:Diagnosis of alopecia areata could be made in 30 (100%) cases in transverse sections and 28 cases (93.3%) in vertical sections. The number of hair follicles available for evaluation was more in the transverse section. Nanogen follicles and miniaturization of follicles were better visualized in the transverse sections. However the catagen and telogen follicles were noted in both vertical and transverse sections but the number and the ratio of anagen and telogen hair follicles could be better assessed in the transverse sections. Presence of peribulbar lymphocytic infiltrate, eosinophils and pigment casts were noted in both transverse and vertical sections.Conclusions:Transverse sections provide a better assessment of the histological features of alopecia areata than vertical sections and thus should be preferred.

Diagnostic usefulness of a peribulbar eosinophilic infiltrate in alopecia areata.

The histopathologic diagnosis of alopecia areata (AA) may be difficult in the chronic stage in which the presence of a peribulbar lymphocytic infiltrate is not definite. An eosinophilic infiltrate has been reported as a relatively common histopathologic finding and a helpful diagnostic feature in AA. To investigate the frequency and diagnostic usefulness of an eosinophilic infiltrate around the hair bulbs or within the fibrous tracts during the chronic stage of AA. A retrospective review was conducted at Chungbuk National University Hospital. A total of 162 scalp biopsy specimens of AA were analyzed. The frequency of a peribulbar eosinophilic infiltrate in AA. In 30 of 162 specimens (18.5%) of AA in all stages, eosinophils were found around the hair bulbs with variable density but were not identified in the fibrous tracts of any specimen. Eosinophils around the hair bulbs were detected in 24 of 78 specimens (30.8%) of the acute stage of AA in which a peribulbar lymphocytic infiltrate was present, and eosinophils were densely infiltrated in 6 of these specimens (7.7%). In contrast, in the chronic stage of AA in which a peribulbar lymphocytic infiltrate was sparse or absent, eosinophils around the hair bulbs were found in only 6 of 84 specimens (7.1%); furthermore, eosinophils were sparsely present in all specimens. Pigmentary incontinence around the hair follicles was found in 58 of 84 specimens (69.0%), follicular miniaturization in 52 (61.9%), and shift to the catagen or telogen phase in 46 (54.8%). An eosinophilic infiltrate around the hair bulbs or within the fibrous tracts is not a common finding in the histopathologic characteristics of AA, especially in the chronic stage of the disease. Thus, the diagnostic usefulness of the eosinophilic infiltrate is limited to few cases of AA in the chronic stage. Other histopathologic findings, such as pigmentary incontinence around the hair follicles, follicular miniaturization, and shift to the catagen or telogen phase, are more useful diagnostic features in the cases of AA not showing a definite peribulbar lymphocytic infiltrate.

Vertical vs. transverse sections of scalp biopsy specimens: a pilot study on the comparison of the diagnostic value of two techniques in alopecia

Using both vertical and transverse sections is preferred for histopathological diagnosis of alopecia. However, in cases in which only a single biopsy is taken, it is not clear which type of sectioning is better. To compare the diagnostic value of transverse and vertical sections. In total, 53 patients with alopecia were enrolled in the study. Two biopsies were taken from each patient, and cut into either transverse or vertical sections. The clinical and histopathological findings were evaluated together for the definitive diagnosis. After the study period, a pathologist randomly re-evaluated the sections. We compared the histopathological diagnoses with the definitive diagnoses, and determined the sensitivity and specificity of each method. A definitive diagnosis was made for 47 patients (88.7%). Of these, 30 (63.8%) had noncicatricial and 17 (36.2%) had cicatricial alopecia, and the diagnosis was made by transverse and vertical sections for 43 (91.5%) and 39 (88%), respectively (P > 0.05; sensitivity; 91.5% vs. 82%). All 30 patients with noncicatricial alopecia were diagnosed by transverse sections, and 25 (83.3%) of the 30 were diagnosed with vertical sections (P = 0.05; sensitivity 100% vs. 83.3%). Of the 17 patients with cicatricial alopecia, 13 (76.5%) and 14 (82.4%) patients were diagnosed by transverse and vertical sections, respectively (P > 0.05; sensitivity 76.5% vs. 82.4%). Five patients with lichen planopilaris were diagnosed by vertical sections, and one by transverse sections. There were several limitations to the study: (i) statistical subtype analysis could be performed only for alopecia areata; (ii) no conclusion could be drawn about the interobserver reliability of two sections; and (iii) having the pathologist-blinded study performed retrospectively might have caused a recall bias. If only a single biopsy specimen is available, it may be preferable to have transverse sections in cases of suspected noncicatricial alopecia, and vertical sections in cases of suspected lichen planopilaris. Either type of sectioning is suitable for cicatricial alopecia when lichen planopilaris is clinically unlikely.

Frontal fibrosing alopecia: a review of eleven patients

Frontal fibrosing alopecia (FFA) is a primary lymphocytic cicatricial alopecia with a distinctive clinical pattern of progressive frontotemporal hairline recession. Our purpose was to describe the clinical and histopathological features as well as the response to treatment of eleven cases of FFA diagnosed at the Trichology Consultation, over three years. A retrospective case note review was performed of eleven adult patients with FFA. The clinical data as well the histopathologic findings and laboratory tests were accessed. The patients were treated with different drugs, depending on the stage of the disease. The age of onset of the alopecia ranged from 45 to 80 years. Ten patients (90.9%) were postmenopausal women. All patients had progressive and symmetrical alopecia localized to the frontal and temporal hairline. Seven patients (63.6%) had marked decreased to complete loss of eyebrows and in four patients axillar alopecia was also evident. Laboratory investigations were normal. Scalp biopsy specimens from the anterior hairline showed similar findings. No significant improvement was observed in the majority of cases. Differential diagnosis should take into account several other conditions. It seems there is no effective treatment proven with an appropriate level of evidence in the management of FFA.

Treatment of alopecia areata: “What is new on the horizon?”

New drug treatment opportunities based on the results of a genome-wide association study, which implicate T cell and natural killer (NK)-cell activation pathways, are leading to new approaches in future clinical trials of alopecia areata. Special attention is being given to the UL 16-binding protein (ULBP3) gene cluster on chromosome 6q25, as these genes make the NKG2D-activating ligand or signal that can trigger the NKG2D receptor, initiating an autoimmune response. A greater expression of ULBP3 has also been found in hair follicles in scalp biopsy specimens from patients with active disease. It is now postulated that the characteristic T cell "swarm of bees" infiltrate seen in alopecia areata is the result of T cells being attracted to the hair follicle by NKG2D-activating ligands. Future treatment approaches for alopecia areata include use of drugs that: (i) block the NKGD-activating ligand and NKG2D receptor interaction, (ii) halt activated T cells, or (iii) modification of the inflammatory cytokine network. Many drugs currently being used or being evaluated for other autoimmune diseases that work through these mechanisms might prove to be very effective in alopecia areata.

Dermoscopic features of alopecia areata and their correlation with clinicopathological manifestations

Objective To observe the microstructural changes in lesions of alopecia areata (AA) with dermoscopy and to evaluate their correlation with clinicopathological manifestations. Methods The area of alopecia of 62 patients with AA and 44 patients with other types of hair loss were observed by using a noncontact polarized dermoscope (Dermlite, USA). Clinical data on and laboratory findings from these patients were collected. Pathological examination was carried out with scalp biopsy specimens from the alopecia area of 15 AA patients. Results Characteristic dermoscopic signs of AA included yellow dots, black dots, broken hairs, exclamation mark hairs, short vellus hair and newly-grown short hairs. Among these signs, yellow dots showed the highest prevalence (83.9%). Exclamation mark hairs, black dots and broken hairs were rather specific signs for AA, and the prevalence of the three signs was positively correlated with disease activity and positivity rate of hair-pull test. A positive correlation was also noted between the prevalence of elevated thyroid peroxidase antibody levels and positivity rate of hair-pull test (r = 0.269, P ＜ 0.05 ) as well as prevalence of broken hairs (r = 0.445, P ＜ 0.05), and between the prevalence of yellow dots and that of keratinous plug in follicular orifice. There was a negative correlation between the prevalence of newly-grown short hairs and perifollicular mast cell infiltration and between the prevalence of black dots and the anagen/catagen ratio. Conclusions Yellow dots can serve as a preliminary screening marker for AA. Exclamation mark hairs, black dots and broken hairs are highly sensitive for the confirmation of diagnosis of AA, and often predict progressive AA.Dermoscopic signs are well correlated to the histopathology features of AA, and may be useful for the evaluation of disease severity and guidance on the treatment of AA. Key words: Alopecia areata; Dermoscopy; Pathologic processes

Trichophyton rubrum suppurative tinea of the bald area of the scalp

An 83-year-old man presented with an approximately 1-year history of an extensive inflammatory purulent crusted lesion in the bald area of the scalp diagnosed as tinea caused by Trichophyton rubrum. The scalp biopsy specimen showed suppurative folliculitis with perifollicular abscesses in upper dermis, and periodic acid-Schiff-positive fungal elements within the hair follicles and in the hyperkeratotic horny layer. The infection probably spread from diseased fingernails. A cure of the scalp lesion was achieved 2 months after starting daily oral treatment with 250 mg terbinafine. To our knowledge, the case presented is the first in which a suppurative abscess-forming T. rubrum infection of the bald area of the scalp in an immunocompetent man has been described.

The spectrum of hair loss in patients with mycosis fungoides and Sézary syndrome

Alopecia can be a manifestation of mycosis fungoides (MF) and Sézary syndrome (SS), but the prevalence is unknown. We sought to describe the clinicopathologic presentation and molecular features of alopecia in patients with MF/SS. A retrospective chart review of a prospectively collected MF/SS database was used to identify patients with alopecia. The National Alopecia Areata Registry was used to identify patients with self-reported cutaneous T-cell lymphoma. Among 1550 patients with MF/SS, 38 patients with patchy, total-scalp, or universal alopecia were identified. Thirteen of 38 (34%) had patchy alopecia clinically identical to alopecia areata. Scalp biopsy specimens were available in 5 of the 13 patients. Specimens from 4 patients had atypical T lymphocytes within the follicular epithelium or epidermis, and that from two patients had a histology of follicular mucinosis. The remaining 25 of 38 (66%) patients with MF/SS included 20 with alopecia within discreet patch/plaque or follicular lesions of MF and 5 with total-body hair loss, which presented only in those with generalized erythroderma and SS. This was a retrospective study done at one cancer center. Biopsy specimens of alopecia were not available for every patient. Alopecia was observed in 2.5% of patients with MF/SS, with alopecia areata-like patchy loss in 34% and alopecia within MF lesions in 66%.

Expanding the spectrum of frontal fibrosing alopecia: A unifying concept

In frontal fibrosing alopecia (FFA), scalp alopecia dominates the clinical picture. However, eyebrow loss and hair loss in other body sites may also occur; this has been documented clinically, but rarely histopathologically. We describe the clinicopathological findings of 13 cases of FFA, with histopathologic data from the scalp, eyebrow, and body hair. Thirteen patients with a diagnosis of FFA, seen between 2006 and 2008, were included. Scalp biopsies were performed in all patients for histology and direct immunofluorescence (DIF). Biopsy specimens for histology were taken from the eyebrow in 6 patients and from the upper limb in 5 patients. All 13 patients were female, 11 of whom were postmenopausal. The median age at onset of alopecia was 57 years. Clinical examination revealed a band of frontal hairline recession in all patients. Eyebrow loss was present clinically in all patients, with loss of body hair in 10 of 13. Histopathologic examination of the scalp, eyebrow, and upper limb skin biopsy specimens showed similar features, including a marked reduction in the number of hair follicles and a perifollicular lymphoid cell infiltrate with perifollicular fibrosis. Direct immunofluorescence was negative in all cases. Not all patients consented to biopsies of the eyebrows or upper limbs. Eyebrow and peripheral body hair loss is not uncommon in FFA-a finding that is likely underreported. We have demonstrated that alopecia of the upper limbs in FFA is indeed common and, histopathologically, shows features of lichen planopilaris and scarring, similar to findings in the scalp and eyebrows. Consequently, the process of lichen planopilaris with scarring alopecia is generalized rather than localized only to the frontal scalp and eyebrows.

Potential Involvement of the Stem Cell Factor Receptor c-kit in Alopecia Areata and Androgenetic Alopecia: Histopathological, Immunohistochemical, and Semiquantitative Investigations

Alopecia areata (AAR) and androgenetic alopecia (AGA) are two major forms of alopecia based on altered hair growth condition. In general, the cell cycle is regulated by several mechanisms including the stem cell factor/c-kit signaling. To assess a role for stem cell activity in alopecia, we performed histopathological, immunohistochemical, and semiquantitative analyses of c-kit as well as Ki-67 in scalp biopsy specimens obtained from 14 patients with AAR, 18 patients with AGA, and 6 age-matched control subjects, using the specific antibodies. Formalin-fixed, paraffin-embedded skin sections were examined. Immunoreactivities for Ki-67 and c-kit were localized in keratinocytes and melanocytes in the outermost layer of hair follicles. The mean length of hair follicles was significantly shorter in the AAR and AGA groups than in the control group. The mean number of Ki-67-immunoreactive cells per follicle was significantly reduced in the AAR and AGA groups as compared with the control group. The mean number of c-kit-immunoreactive cells per follicle was significantly increased in the AAR and AGA groups as compared with the control group. Our results indicate that c-kit is upregulated in the hair follicle cells in these forms of alopecia, and suggest that the upregulation reflects a negative feedback mechanism in response to possible downregulation of the ligand stem cell factor.

Scarring alopecia: clinical and pathologic study of 54 African‐American women

Cicatricial or scarring alopecia results in the destruction of hair follicles and is a significant cosmetic concern in African-American women. To correlate the clinical examination and histologic findings in African-American women with scarring alopecia with a history of hairstyling practices. We reviewed retrospectively the medical records and scalp biopsy specimens of 54 women with scarring alopecia. Patients were selected from two dermatologic practices in the Detroit Metropolitan area. Alopecia commonly presents in patients who use a variety of traumatic haircare techniques, including chemical and physical straighteners, traction, braiding, hair extensions, hair gluing, and chemical curls. Histologic findings are centered around the follicular infundibulum with a lymphocytic infiltrate and perifollicular fibrosis. Traumatic hairstyling techniques are common in African-American women, and all result in a similar picture of a peri-infundibular lymphocytic infiltrate and fibrosis, leading to alopecia.