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1.
Pediatr Dermatol ; 36(5): 640-645, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31294493

RESUMO

BACKGROUND/OBJECTIVES: Trichoscopic findings characteristic of alopecia areata have been established in adults. The objective of the study was to assess trichoscopic findings in children with alopecia areata. METHODS: Retrospective analysis of trichoscopic findings in 50 children (3-11 years old) and 50 adults (19-31 years old) with alopecia areata was performed. RESULTS: Yellow dots were less commonly detected in children compared with adults (26/50, 52% vs 48/50, 96%). Pigtail hairs and empty follicular openings were more commonly observed in children compared with adults (14/50, 28% vs 2/50, 4% and 40/50, 80% vs 16/50, 32%, respectively). No significant difference in the frequency of other trichoscopic features between children and adults was found. Black dots, broken hairs, exclamation mark hairs, and tapered hairs were detected in 20/50 (40%), 27/50 (54%), 22/50 (44%), and 6/50 (12%) children, respectively, and in 26/50 (52%), 27/50 (54%), 20/50 (40%), and 11/50 (22%) adults, respectively. Triangular hairs (short hidden hairs), short vellus hairs, and upright regrowing hairs were observed in 22/50 (44%), 35/50 (70%), and 23/50 (46%) children, respectively, and in 24/50 (48%), 37/50 (74%), and 28/50 (56%) adults, respectively. Pohl-Pinkus constrictions were present in 2/50 (4%) children and 4/50 (8%) adults. CONCLUSIONS: The most common trichoscopic findings of alopecia areata in children are empty follicular openings and short vellus hairs. Pigtail hairs and empty follicular openings are more commonly presented in children compared with adults. In contrast, yellow dots are less commonly observed in children compared with adults. Triangular hairs (short hidden hairs) are new trichoscopic findings of alopecia areata.


Assuntos
Alopecia em Áreas/patologia , Dermoscopia , Adulto , Fatores Etários , Criança , Pré-Escolar , Feminino , Folículo Piloso/patologia , Humanos , Masculino , Estudos Retrospectivos , Couro Cabeludo/patologia , Índice de Gravidade de Doença , Adulto Jovem
3.
J Cutan Pathol ; 46(9): 653-658, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30989699

RESUMO

BACKGROUND: Alopecia areata (AA) is believed to have an autoimmune mechanism in which the hair follicles are targeted by CD4+ and CD8+ lymphocytes. Studies investigating the autoimmune mechanism of other cutaneous diseases, including vitiligo, showed that Treg is a component of cutaneous immune privilege. Our study uses immunohistochemical staining in formalin-fixed, paraffin-embedded tissue to examine the percentage of CD4+ FoxP3+ , CD25+ FoxP3+ , and CD8+ FoxP3+ Treg in AA in human specimens. METHODS: Immunohistochemical double staining for CD4+ FoxP3+ , CD25+ FoxP3+ , and CD8+ FoxP3+ was performed on 12 AA cases and 12 other autoimmune and non-autoimmune cutaneous diseases. The frequency of CD4+ FoxP3+ , CD25+ FoxP3+ , and CD8+ FoxP3+ Treg was counted and expressed as a percentage of total CD4+ , CD25+ , and CD8+ lymphocytes, respectively, in order to account for intersample inflammatory response variability. RESULTS: There was a significant reduction in the mean frequency of CD4+ FoxP3+ and CD25+ FoxP3+ in AA when compared to other autoimmune and non-autoimmune cutaneous diseases. CONCLUSION: Treg is significantly lower in AA when compared to other cutaneous diseases. Additionally, this immunohistochemical-staining protocol may be useful to evaluate Treg in formalin-fixed, paraffin-embedded specimens for other cutaneous diseases. Studies examining Treg in AA and other cutaneous diseases may have implications for future interventions.


Assuntos
Alopecia em Áreas/imunologia , Doenças Autoimunes/imunologia , Folículo Piloso/imunologia , Linfócitos T Reguladores/imunologia , Alopecia em Áreas/patologia , Doenças Autoimunes/patologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Feminino , Folículo Piloso/patologia , Humanos , Masculino , Linfócitos T Reguladores/patologia
4.
JAMA Dermatol ; 155(5): 564-571, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30916724

RESUMO

Importance: Diverse assessment tools and classification have been used for alopecia areata; however, their prognostic values are limited. Objective: To identify the topographic phenotypes of alopecia areata using cluster analysis and to establish a prediction model and grading system for stratifying prognoses. Design, Setting, and Participants: A retrospective cohort study of 321 patients with alopecia areata who visited a single tertiary referral center between October 2012 and February 2017 and underwent 4-view photographic assessment. Exposures: Clinical photographs were reviewed to evaluate hair loss using the Severity of Alopecia Tool 2. Topographic phenotypes of alopecia areata were identified using hierarchical clustering with Ward's method. Differences in clinical characteristics and prognosis were compared across the clusters. The model was evaluated for its performance, accuracy, and interobserver reliability by comparison to conventional methods. Main Outcomes and Measures: Topographic phenotypes of alopecia areata and their major (60%-89%) and complete regrowth probabilities (90%-100%) within 12 months. Results: A total of 321 patients were clustered into 5 subgroups. Grade 1 (n = 200; major regrowth, 93.4%; complete regrowth, 65.2%) indicated limited hair loss, whereas grades 2A (n = 66; major regrowth, 87.8%; complete regrowth, 64.2%) and 2B (n = 20; major regrowth, 73.3%; complete regrowth, 45.5%) exhibited greater hair loss than grade 1. The temporal area was predominantly involved in grade 2B, but not in grade 2A, despite being comparable in total extent of hair loss. Grade 3 (n = 20; major regrowth, 45.5%; complete regrowth, 25.5%) included diffuse or extensive alopecia areata, and grade 4 (n = 15; major regrowth, 28.2%; complete regrowth, 16.7%) corresponded to alopecia (sub)totalis. No significant differences in prognosis (hazard ratio [HR] for major regrowth, 0.79; 95% CI, 0.56-1.12) were found between grades 2A and 1, whereas grades 2B (HR, 0.41; 95% CI, 0.21-0.81), 3 (HR, 0.24; 95% CI, 0.12-0.50), and 4 (HR, 0.16; 95% CI, 0.06-0.39) had significantly poorer response. Among multiple models, the cluster solution had the greatest prognostic performance and accuracy. The tree model of the cluster solution was converted into the Topography-based Alopecia Areata Severity Tool (TOAST), which revealed an excellent interobserver reliability among 4 dermatologists (median quadratic-weighted κ, 0.89). Conclusions and Relevance: Temporal area involvement should be independently measured for better prognostic stratification. The TOAST is an effective tool for describing the topographical characteristics and prognosis of hair loss and may enable clinicians to establish better treatment plans.


Assuntos
Alopecia em Áreas/patologia , Cabelo/crescimento & desenvolvimento , Modelos Teóricos , Adulto , Alopecia em Áreas/classificação , Análise por Conglomerados , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fenótipo , Prognóstico , Reprodutibilidade dos Testes , Estudos Retrospectivos , Adulto Jovem
5.
J Dermatol ; 46(5): 418-421, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30843255

RESUMO

Despite patchy hair loss being typically observed in alopecia areata (AA), similar lesions can be seen in other forms of alopecia and the diagnosis is sometimes challenging. Of note, patchy primary scarring alopecia (SA) needs to be clearly distinguished from AA as SA can leave permanent hair loss. Herein, we report a previously unreported case of AA coexisting with SA successfully diagnosed by detailed trichoscopic investigation. A 42-year-old woman visited us with patchy hair loss lesions on the scalp. On physical examination, alopecic lesions sized up to 2 cm in diameter were observed in the right temporal and parietal regions. A gentle hair pull test collected dystrophic anagen hairs from some patches. Trichoscopy detected tapering hairs and black dots. The diagnosis of AA was made. However, some reddish patches were totally hair pull test negative, urging us to further evaluate the remaining lesions. Additional trichoscopic investigation revealed the disappearance of follicular ostia and the presence of a white and milky-red area and peripilar scales, suggestive of SA. In histology, the clinically AA lesion showed peribulbar cell infiltration, while the potentially SA lesion demonstrated inflammatory cell infiltration around the isthmus and the decrease in hair follicles, some of which were replaced by fibrotic tissue. The final diagnosis of AA coexisting with SA was made. Intralesional corticosteroid injection improved AA but not SA. These findings emphasize the need for thorough trichoscopic examination for accurate diagnoses of rare hair loss conditions.


Assuntos
Alopecia em Áreas/diagnóstico por imagem , Cicatriz/diagnóstico por imagem , Dermoscopia/métodos , Cabelo/diagnóstico por imagem , Adulto , Alopecia em Áreas/complicações , Alopecia em Áreas/patologia , Cicatriz/etiologia , Cicatriz/patologia , Diagnóstico Diferencial , Feminino , Cabelo/patologia , Humanos , Couro Cabeludo/diagnóstico por imagem
8.
Am J Dermatopathol ; 41(2): 122-127, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30640755

RESUMO

BACKGROUND: Androgenetic alopecia (AGA) results from shortening of the anagen phase of the hair cycle and, subsequently, miniaturization of hair follicles. Alopecia areata (AA) is a disease of autoimmunity where T cells attack anagen hair follicles and shows multifactorial etiology. Dickkopf-1 (DKK-1) is a gene that is responsible for transformation of anagen to catagen, which suggests that it is involved in development of both diseases. OBJECTIVES: To evaluate the tissue levels of dickkopf-1 in male patients with AGA and AA in comparison with controls, in an attempt to know its role in the pathogenesis of both disorders. METHODS: DKK-1 immunohistochemical expression was evaluated in lesional scalp biopsies taken from 20 male patients with AGA evaluated clinically by the modified Norwood-Hamilton score, 20 male patients with AA evaluated clinically by SALT score, and 20 healthy controls within the same age and sex of the studied patients. RESULTS: A highly significant difference in DKK-1 expression between patients with AGA and healthy controls was found (P2 < 0.001). There were also significant differences in DKK-1 expression between patients with AA and healthy controls (P3 = 0.013), and between both patient groups (P1 = 0.002). CONCLUSIONS: Both AGA and AA showed significant increase in DKK-1 immunohistochemical expression. This may enhance the idea of its possible role in the pathogenesis of AGA and AA, and being a new target for treatment of these hair disorders.


Assuntos
Alopecia em Áreas/metabolismo , Alopecia/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/biossíntese , Adulto , Alopecia/patologia , Alopecia em Áreas/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
11.
J Cosmet Dermatol ; 18(4): 1128-1132, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30294905

RESUMO

BACKGROUND: Alopecia areata (AA) is a multifactorial disease in which tumor necrosis factor alpha (TNF-α) plays an important role. OBJECTIVE: To study the effect of oral pulse steroids on both serum and tissue levels of TNF-α in AA patients. METHODS: Skin biopsies and serum samples were collected from 20 patients with patchy AA before and after treatment (oral prednisolone for two consecutive days every week for 3 months) for determination of the levels of TNF-α levels using ELISA technique. RESULTS: Both serum and tissue levels of TNF-α in AA patients were significantly higher than in controls before (P < 0.001) as well as after treatment (P = 0.0169 and P = 0.3051), respectively. The duration of disease negatively correlated with tissue TNF-α before treatment (P < 0.0001). Serum and tissue levels of TNF-α dropped significantly after treatment (P < 0.0001). The percentage of reduction of both tissue and serum TNF-α levels correlated positively with the percentage of clinical improvement (r = 0.682, P = 0.0009; r = 0.567, P = 0.009, respectively). CONCLUSION: TNF-α plays an important role in the evolution of AA lesions, and alteration in both serum and tissue levels of TNF-α could be considered one of the important mechanisms of action of systemic oral pulse steroids in the treatment of AA.


Assuntos
Alopecia em Áreas/tratamento farmacológico , Glucocorticoides/farmacologia , Pele/patologia , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Administração Oral , Adolescente , Adulto , Alopecia em Áreas/sangue , Alopecia em Áreas/patologia , Biópsia , Estudos de Casos e Controles , Feminino , Glucocorticoides/uso terapêutico , Humanos , Masculino , Prednisolona/farmacologia , Prednisolona/uso terapêutico , Pulsoterapia , Pele/efeitos dos fármacos , Resultado do Tratamento , Fator de Necrose Tumoral alfa/análise , Adulto Jovem
12.
J Cosmet Dermatol ; 18(2): 659-664, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30556317

RESUMO

BACKGROUND: Alopecia areata (AA) is multifactorial disease mostly autoimmune affecting anagen hair follicles. Many researchers hypothesize that adequate retinoic acid (RA) levels are important for proper hair follicle behavior. Previous animal studies revealed increase in RA synthesis proteins and decrease in RA degradation proteins in AA patients when compared with controls. OBJECTIVE: To evaluate cellular retinol-binding protein-1 expression in lesional skin of alopecia areata in comparison with controls, in an attempt to know its role in the pathogenesis of alopecia areata . METHODS: Immunohistochemical expression of cellular retinol-binding protein-1 CRBP1 was evaluated in skin biopsies taken from lesions of alopecia areata in 30 patients and 10 normal biopsy specimens taken from skin of healthy controls (HC) who were within the same age and sex. RESULTS: CRBP1 expression was significantly increased in lesional alopecia areata skin in comparison with normal skin of controls (P < 0.001*). Significant positive correlation was found between expression of CRBP-1 and percentage of hair loss in the scalp (SALT score; r = 0.840, P = <0.001). CONCLUSION: These results may enhance the idea of the possible role of CRBP1 in the pathogenesis of AA, and ensuring the importance of its level in AA treatment.


Assuntos
Alopecia em Áreas/patologia , Proteínas Celulares de Ligação ao Retinol/metabolismo , Pele/patologia , Adolescente , Adulto , Alopecia em Áreas/diagnóstico , Biópsia , Estudos de Casos e Controles , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas Celulares de Ligação ao Retinol/análise , Couro Cabeludo , Índice de Gravidade de Doença , Adulto Jovem
15.
Drug Des Devel Ther ; 12: 2323-2335, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30100707

RESUMO

Alopecia areata (AA) is a common hair loss disorder worldwide with characteristic exclamation mark hairs. Although AA is self-limited, it can last for several months or even years in some patients. Currently, there is no US Food and Drug Administration-approved treatment for AA. Many off-label treatments are available but with limited efficacy. Through a better understanding of molecular biology, many targeted therapies have emerged as new alternatives for various autoimmune diseases. Various janus kinase (JAK) and signal transducer and activator of transcription (STAT) proteins form signaling pathways, which transmit extracellular cytokine signals to the nucleus and induce DNA transcriptions. By inhibiting JAK, T-cell-mediated inflammatory responses are suppressed. Increasing evidence suggests that JAK inhibitors (JAKis) are effective in the treatment of many autoimmune diseases, including AA. Among these, several studies on tofacitinib, ruxolitinib, and baricitinib in AA had been published, demonstrating promising outcomes of these agents. Unlike oral formulations, efficacy of topical forms of tofacitinib and ruxolitinib reported in these studies is still unsatisfactory and requires improvement. This review aims to summarize evidence of the efficacy and safety of JAKis in the treatment of AA.


Assuntos
Alopecia em Áreas/tratamento farmacológico , Inibidores de Janus Quinases/farmacologia , Janus Quinases/antagonistas & inibidores , Piperidinas/farmacologia , Pirimidinas/farmacologia , Pirróis/farmacologia , Alopecia em Áreas/metabolismo , Alopecia em Áreas/patologia , Animais , Humanos , Inibidores de Janus Quinases/química , Janus Quinases/metabolismo , Piperidinas/química , Pirimidinas/química , Pirróis/química
16.
Dermatology ; 234(3-4): 137-147, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30092597

RESUMO

BACKGROUND: Androgenetic alopecia (AGA) and alopecia areata (AA) are common causes of alopecia which can sometimes be difficult to differentiate clinically. Horizontal sections of scalp biopsies are used to study non-cicatricial alopecias due to the ability to perform both quantitative and morphometric analysis of hair follicles on them. METHODS: It was a prospective, cross-sectional study conducted to assess the utility of horizontal sections to differentiate between the alopecias. Fifty-two cases were included: 20 cases of male AGA, 11 of female AGA and 21 cases of AA. After clinical examination and dermoscopy, a skin biopsy was taken and subjected to transverse sectioning. Histopathological assessment was done by two dermatopathologists blinded to clinical details. RESULTS: Among the quantitative parameters, terminal:vellus hair ratio (3.08 in AGA and 1.83 in AA, p = 0.0091) and anagen:non-anagen hair ratio (9.25 in AGA and 3.56 in AA, p = 0.0021) were significantly lower in AA. In qualitative parameters, peribulbar inflammation was seen in 63% of AA cases (p = 0.0001). Pigment casts were seen in twice the number of AA (57%) than AGA (26%) cases. Broad avascular stelae and focal trichomalacia were seen in 9.5% of AA cases. CONCLUSION: Besides peribulbar inflammation, we found a lower anagen:non-anagen hair ratio and presence of pigment casts in transverse sections of scalp biopsies favouring AA over AGA.


Assuntos
Alopecia em Áreas/patologia , Alopecia/patologia , Couro Cabeludo/patologia , Adolescente , Adulto , Biópsia/métodos , Estudos Transversais , Feminino , Folículo Piloso/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Adulto Jovem
17.
J Dermatol ; 45(9): 1071-1079, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29963718

RESUMO

Intravenous corticosteroid pulse therapy (pulse therapy) has been reported to be effective for rapidly progressive alopecia areata (RP-AA). Mostly, a single 3-day administration of corticosteroid (methylprednisolone 500 mg/day) has been performed in Japan; however, to what extent additional administrations improve the outcome has not been fully elucidated. To assess the advantage of repeating the pulse therapy to RP-AA cases refractory to the initial intervention, retrospective clinicopathological analysis was performed. Detailed chronological analysis was conducted in eight cases (one man and seven women; average age, 38.3 ± 10.4 years) demonstrating total scalp hair loss 3 months after the first pulse therapy and treated with additional rounds of the pulse therapy. All cases manifested total hair loss, scalp edema, itch or pain on the scalp after the initial intervention. Histopathological analyses of affected lesions prior to additional pulse therapies revealed persisting dense perifollicular lymphocytic inflammation in all cases. Interestingly, such inflammatory change tended to be severer when compared with previously reported pulse therapy good responders. Extra pulse therapy resulted in partial regrowth of terminal hairs in three out of eight cases, but all of them experienced relapse in the long run. The literature review also suggested limited efficacy of repeating pulse therapy to severe AA cases. These findings suggested that the efficacy of currently conducted repetitive pulse therapy is limited in RP-AA cases with extensive perifollicular inflammation and resistant to the initial pulse therapy. Modulation of the dose and the interval of intervention, in combination with alternative approaches, may be required to achieve a successful outcome.


Assuntos
Alopecia em Áreas/tratamento farmacológico , Resistência a Medicamentos , Glucocorticoides/uso terapêutico , Metilprednisolona/uso terapêutico , Administração Intravenosa , Adolescente , Adulto , Alopecia em Áreas/patologia , Progressão da Doença , Feminino , Seguimentos , Glucocorticoides/farmacologia , Cabelo/efeitos dos fármacos , Cabelo/crescimento & desenvolvimento , Cabelo/patologia , Humanos , Japão , Masculino , Metilprednisolona/farmacologia , Pessoa de Meia-Idade , Pulsoterapia , Recidiva , Estudos Retrospectivos , Resultado do Tratamento
18.
Cell Transplant ; 27(6): 994-1004, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29871523

RESUMO

Alopecia areata (AA) is an autoimmune hair loss disease with infiltration of proinflammatory cells into hair follicles. Current therapeutic regimens are unsatisfactory mainly because of the potential for side effects and/or limited efficacy. Here we report that cultured, transduced fibroblasts, which express the immunomodulatory molecule indoleamine 2,3-dioxygenase (IDO), can be applied to prevent hair loss in an experimental AA model. A single intraperitoneal (IP) injection of IDO-expressing primary dermal fibroblasts was given to C3H/HeJ mice at the time of AA induction. While 60-70% of mice that received either control fibroblasts or vehicle injections developed extensive AA, none of the IDO-expressing fibroblast-treated mice showed new hair loss up to 20 weeks post injection. IDO cell therapy significantly reduced infiltration of CD4+ and CD8+ T cells into hair follicles and resulted in decreased expression of TNF-α, IFN-γ and IL-17 in the skin. Skin draining lymph nodes of IDO fibroblast-treated mice were significantly smaller, with more CD4+ CD25+ FoxP3+ regulatory T cells and fewer Th17 cells than those of control fibroblast and vehicle-injected mice. These findings indicate that IP injected IDO-expressing dermal fibroblasts can control inflammation and thereby prevent AA hair loss.


Assuntos
Alopecia em Áreas/terapia , Fibroblastos/transplante , Indolamina-Pirrol 2,3,-Dioxigenase/genética , Alopecia em Áreas/patologia , Animais , Terapia Baseada em Transplante de Células e Tecidos , Células Cultivadas , Citocinas/análise , Modelos Animais de Doenças , Fibroblastos/citologia , Fibroblastos/metabolismo , Camundongos Endogâmicos C3H , Transdução Genética
19.
Am J Clin Dermatol ; 19(5): 679-694, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29948959

RESUMO

Cutaneous and systemic lupus erythematosus (SLE) commonly involves the hair and scalp. Alopecia can result from direct activity of disease on the scalp or from the state of physical stress in the form of telogen effluvium. Discoid lupus erythematosus and lupus panniculitis/profundus are known to cause scarring alopecia, while accumulation of recent studies has shown that non-scarring alopecia in SLE may have different subtypes, comprising lupus erythematosus-specific and lupus erythematosus-nonspecific changes on histology. This review aims to summarize the clinical pattern, trichoscopic, histopathological, and direct immunofluorescence features of different types of alopecia in cutaneous and systemic lupus erythematosus, as well as exploring their relationship with SLE disease activity.


Assuntos
Alopecia em Áreas/imunologia , Fármacos Dermatológicos/uso terapêutico , Lúpus Eritematoso Cutâneo/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Alopecia em Áreas/diagnóstico , Alopecia em Áreas/tratamento farmacológico , Alopecia em Áreas/patologia , Antimaláricos/uso terapêutico , Dermoscopia/métodos , Diagnóstico Diferencial , Progressão da Doença , Glucocorticoides/uso terapêutico , Cabelo/imunologia , Cabelo/patologia , Humanos , Lúpus Eritematoso Cutâneo/diagnóstico , Lúpus Eritematoso Cutâneo/tratamento farmacológico , Lúpus Eritematoso Cutâneo/patologia , Lúpus Eritematoso Sistêmico/diagnóstico , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Lúpus Eritematoso Sistêmico/patologia , Microscopia Confocal , Prognóstico , Recidiva , Couro Cabeludo/imunologia , Couro Cabeludo/patologia , Índice de Gravidade de Doença , Resultado do Tratamento
20.
Br J Dermatol ; 179(5): 1033-1048, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29791718

RESUMO

BACKGROUND: Alopecia areata is a disorder that results in nonscarring hair loss. The psychological impact can be significant, leading to feelings of depression and social isolation. Objectives In this article, we seek to review the pathophysiological mechanisms proposed in recent years in a narrative fashion. METHODS: We searched MEDLINE and Scopus for articles related to alopecia areata, with a particular emphasis on its pathogenesis. RESULTS: The main theory of alopecia areata pathogenesis is that it is an autoimmune phenomenon resulting from a disruption in hair follicle immune privilege. What causes this breakdown is an issue of debate. Some believe that a stressed hair follicle environment triggers antigen presentation, while others blame a dysregulation in the central immune system entangling the follicles. Evidence for the latter theory is provided by animal studies, as well investigations around the AIRE gene. Different immune-cell lines including plasmacytoid dendritic cells, natural killer cells and T cells, along with key molecules such as interferon-γ, interleukin-15, MICA and NKG2D, have been identified as contributing to the autoimmune process. CONCLUSIONS: Alopecia areata remains incurable, although it has been studied for years. Available treatment options at best are beneficial for milder cases, and the rate of relapse is high. Understanding the exact mechanisms of hair loss in alopecia areata is therefore of utmost importance to help identify potential therapeutic targets.


Assuntos
Alopecia em Áreas/imunologia , Doenças Autoimunes/imunologia , Folículo Piloso/imunologia , Privilégio Imunológico , Fatores Imunológicos/uso terapêutico , Alopecia em Áreas/tratamento farmacológico , Alopecia em Áreas/patologia , Animais , Doenças Autoimunes/tratamento farmacológico , Doenças Autoimunes/patologia , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Modelos Animais de Doenças , Folículo Piloso/citologia , Folículo Piloso/patologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Interferon gama/imunologia , Interferon gama/metabolismo , Interleucina-15/imunologia , Interleucina-15/metabolismo , Queratinócitos/imunologia , Queratinócitos/patologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Subfamília K de Receptores Semelhantes a Lectina de Células NK/imunologia , Subfamília K de Receptores Semelhantes a Lectina de Células NK/metabolismo , Recidiva , Linfócitos T/imunologia , Linfócitos T/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/imunologia , Resultado do Tratamento
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