Racial characteristics of alopecia areata in the United States.

BACKGROUND: Epidemiologic studies on the association between race and alopecia areata (AA) are limited. OBJECTIVE: To characterize racial differences of AA in the United States. METHODS: Cross-sectional study of self-registered AA patients and noncases in the National Alopecia Areata Registry (NAAR). We evaluated odds of AA and its subtypes for 5 ethnic/racial groups using logistic regression. A sex-stratified analysis and a sensitivity analysis among dermatologist-confirmed cases were also performed. RESULTS: We identified 9340 AA patients and 2064 noncases. Compared with whites, African Americans had greater odds of AA (odds ratio, 1.77; 95% confidence interval, 1.37-2.28) and Asians had lower odds (odds ratio, 0.40; 95% confidence interval, 0.32-0.50) of AA. The results were consistent in AA subtypes, dermatologist-confirmed cases, and by sex. LIMITATIONS: Residual confounding due to limited number of covariates. Recall or recruitment bias not representative of the entire disease spectrum. Also, outcome misclassification was possible because not all AA cases in the registry were confirmed by dermatologists. CONCLUSION: Our findings suggest higher odds of AA in African Americans and lower odds in Asians compared with whites. Future studies examining racial disparity in AA from clinical and genetic perspectives are warranted for a better understanding of the disease pathogenesis.

The association between rs2476601 polymorphism in PTPN22 gene and risk of alopecia areata: A meta-analysis of case-control studies.

BACKGROUND: The single nucleotide polymorphism (SNP) rs2476601 of the protein tyrosine phosphatase, nonreceptor type 22 (PTPN22) gene has been presented to implicate in the pathogenesis of alopecia areata (AA) in a few association investigations with limited sample size and inconsistent conclusions. METHODS: The aim of the current meta-analysis was to assess and synthesize the presently available data on the connection between rs2476601 and AA vulnerability. Six electronic databases, including EMBASE, PubMed, Web of Science, the Cochrane Library, Wanfang data, and the China National Knowledge Infrastructure database (CNKI), were systematically retrieved for relevant observational studies published previous to November 2018. Total odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs) were analyzed to evaluate the correlation between PTPN22 polymorphism and AA. Risk of bias was estimated according to the Newcastle-Ottawa Scale (NOS). Sensitivity analyses were carried out using the RevMan 5.3 software. RESULTS: In general, 5 case-control studies including 1129 AA patients and 1702 healthy control individuals were obtained for this meta-analysis. The pooled results suggested that rs2476601 SNP was significantly associated with AA susceptibility under allelic model (C vs T, OR = 0.77, 95% CI, 0.64-0.92, P = .003) and recessive model (CC vs CT + TT, OR = 0.73, 95% CI, 0.60-0.88, P = .001). CONCLUSION: On the basis of the results of the current research, the rs2476601 polymorphism of PTPN22 gene is significantly correlated with AA susceptibility. The C-allele and CC-genotype carriers at this locus have a lower risk of AA.

Analysis of trichoscopic signs observed in 24 patients presenting tinea capitis: Hypotheses based on physiopathology and proposed new classification.

INTRODUCTION: Trichoscopy (hair dermoscopy) is a non-invasive and very useful technique for the diagnosis and follow-up of hair and scalp disorders. In tinea capitis, specific aspects of the hair shaft have been described, with the main ones being: comma hair, corkscrew hair, bar code-like hair (BCH) and zigzag hair (ZZH). METHOD: Herein we report on a retrospective study of 24 patients with tinea capitis (TC). All patients underwent trichoscopic examination and mycological culture. RESULTS: Trichoscopy was abnormal in all 24 patients showing hair-shaft abnormalities. We observed three types of images depending on the nature and the mechanism of infection and discuss the different trichoscopic aspects of the hair shaft (comma hair, corkscrew hair, bar code-like hair, zigzag hair, broken hair and black dots) resulting from 3 mechanisms of penetration of the fungus in the hair shaft (endothrix, ectothrix and ectothrix-endothrix). All patients had positive mycological cultures: 15 with trichophytic TC (8 with Trichophyton tonsurans, 5 with T. soudanense and 2 with T. verrucosum) and 9 microsporic TC (7 with Microsporum audouini, and 2 with M. canis). DISCUSSION: We propose for the first time, to our knowledge, a classification of trichoscopic signs of TC. This classification will enable rapid diagnosis and prediction of the nature of the fungus before mycological culture. CONCLUSION: Our study shows the importance of trichoscopy in the diagnosis and monitoring of TC as well as its very good correlation with mycological culture. We propose a new classification of trichoscopic signs dependent on the nature of the mycological agent and the mechanism of infection. Further prospective studies with more patients are needed to confirm this classification.

Association between TAP1 gene polymorphisms and alopecia areata in a Korean population.

The transporter 1 ATP-binding cassette sub-family B (MDR/TAP) gene (TAP1) is located in the major histocompatibility complex class II region, and forms a heterodimer that plays a key role in endogenous antigen presentation pathways. Investigation of polymorphisms identified in these loci has revealed an association with several autoimmune disorders. Alopecia areata (AA) is a common autoimmune disease resulting from T cell-induced damage to hair follicles. The present study documents for the first time a comparison between the allelic and genotypic frequencies of TAP1 single nucleotide polymorphisms (SNPs) in patients with AA and those of a control group, using a direct sequencing method. Our results suggest an association between a promoter SNP (rs2071480) and susceptibility to this disease.

Central centrifugal cicatricial alopecia: what has been achieved, current clues for future research.

Central centrifugal cicatricial alopecia is an inflammatory type of central scalp hair loss seen primarily in women of African descent. The prevalence is unknown, but may vary from 2.7% to 5.7% and increases with age. This review outlines the history and current beliefs and identifies clues for future research for this enigmatic condition. Despite that the cause of central centrifugal cicatricial alopecia is unknown, research is ongoing. The role of cytokeratins, androgens, genetics, and various possible sources of chronic inflammation in disease pathogenesis remain to be elucidated.

Association between IL16 gene polymorphisms and susceptibility to alopecia areata in the Korean population.

BACKGROUND: Alopecia areata (AA) is a chronic disease that presents as non-scarring hair loss. It is thought to be an organ-specific autoimmune disease characterized by T cell infiltrates and cytokine production around anagen-stage hair follicles. Interleukin-16 (IL-16) is a T cell-specific chemoattractant known to be associated with autoimmune disease. OBJECTIVES: This study was conducted to determine whether variation in the IL16 gene contributes to risk for AA in the Korean population. METHODS: A total of 270 control subjects and 229 AA patients were enrolled. Genomic DNA was prepared from peripheral blood. Four single nucleotide polymorphisms (SNPs) (rs17875486 [promoter], rs17875491 [promoter], rs11073001 [exon], rs1803275 [exon]) of the IL16 gene were selected. Genotypes were determined by direct sequencing. Sequence data were analyzed. Multiple logistic regression models were calculated. RESULTS: A significant difference emerged between the AA group and the control group for one SNP (rs17875491) of IL16. A further significant difference was found between patients with and without a family history of AA for a second SNP (rs11073001). CONCLUSIONS: The present study found significant differences pertaining to two SNPs of the IL16 gene between, respectively, AA patients and controls (rs17875491) and AA patients with and without a family history of AA (rs11073001). Thus, IL16 polymorphisms may play a role in the pathophysiology of AA or in the expression of AA phenotypes. Further studies are required to elucidate the role of IL-16 in the pathogenesis and clinical manifestation of AA.

Association analysis of the HLA-C gene in Japanese alopecia areata.

Alopecia areata (AA) is an organ-specific and cell-mediated autoimmune disease involving hair loss, but its pathogenesis remains poorly understood. Many autoimmune diseases are genetically associated with alleles of the human leukocyte antigen (HLA) genes within the major histocompatibility complex. Associations between AA and HLA genes were previously observed in some different ethnic groups. However, the results were inconsistent, and a primary susceptibility HLA gene and/or region has not yet been assigned for AA. The aim of this study was to evaluate whether an allele of the HLA-C locus, HLA-C*07:04, which was strongly associated with AA in Chinese Hans, could be replicated in the Japanese population. The HLA-C locus was genotyped by the SSO method using 156 AA patients and 560 healthy controls. As a consequence, among the 17 alleles detected, only two alleles, C*04:01 (OR = 2.25, CI 95 % = 1.35-3.75, P = 1.84E-03) and C*15:02 (OR = 2.52, CI 95 % = 1.37-4.64, P = 2.90E-03), were significantly associated with AA after Bonferroni correction. Further, the stratification analysis suggested that C*04:01, C*07:02, and C*15:02 represented different AA genetic risk factors in each sub-phenotype.

Genetic association of HLA-DQB1 and HLA-DRB1 polymorphisms with alopecia areata in the Italian population.

BACKGROUND: Alopecia areata (AA) is a multifactorial disease characterized by hair loss especially from the scalp. As for other autoimmune conditions, the major histocompatibility complex (HLA) region is associated with AA susceptibility. OBJECTIVE: To provide evidence for the association of specific HLA-DQB1 and HLA-DRB1 alleles with AA in an Italian population, using a case-control approach. METHODS: We performed a case-control study to investigate whether HLA-DQB1 and -DRB1 alleles predispose to AA in the Italian population. HLA class II typing was performed in 85 patients with AA and 210 healthy controls from the same ethnic group. RESULTS: An increased frequency of DQB1*03, coding for DQ7 heterodimers, and a decreased rate of the DQB1*06 allele were observed in patients when compared with controls; the greatest and significant difference was in the group of cases with a more severe phenotype [AA>50% patients (more than 50% hair loss) vs. controls, P=4·5×10(-3) , P(c)=0·031, odds ratio (OR) 2·01, 95% confidence interval (CI) 1·22-3·31 and P=2·5×10(-3) , P(c)=0·017, OR 0·22, 95% CI 0·07-0·72, respectively]. DQB1*03, serologically related to DQ8 or coding for DQ9 molecules, was not associated with AA susceptibility. Out of all patients, 65·9% carried DQ7 heterodimers compared with 49·5% of the controls (P=7·3×10(-3) , OR 1·97, 95% CI 1·17-3·32) and DQ7 prevalence rose to 76·3% in patients with AA>50% (P=1·7×10(-3) , OR 3·28, 95% CI 1·48-7·27). No significant difference was found in the distribution of DRB1 variants or phenotypes among cases and controls. CONCLUSION: Our data show a correlation between the HLA-DQB1 locus and the occurrence of AA in Italy supporting DQB1*03(DQ7) as a predisposing allele for the disease and the relevance of the HLA genetic test in the clinical management of AA.

The analysis of genetics and associated autoimmune diseases in Chinese vitiligo patients.

Vitiligo is a common skin and hair depigmentary disorder that results from selective destruction of melanocytes. It occurs in a typical multifactorial, polygenic inheritance. Several studies have indicated that vitiligo is associated with some autoimmune diseases. In this paper we examined 6,516 vitiligo patients including clinical characteristics, familial involvement, and their association with other autoimmune diseases. Compared with sporadic vitiligo probands, familial vitiligo probands have earlier age onset and longer disease duration. The prevalences of four autoimmune diseases namely rheumatoid arthritis, chronic urticaria, alopecia areata and psoriasis, were significantly elevated in generalized vitiligo probands and their first-degree relatives. The prevalences of chronic urticaria, rheumatoid arthritis, psoriasis were much higher in familial generalized vitiligo probands. In addition, the prevalences of diabetes mellitus and asthma were also higher in familial vitiligo probands. These findings indicate that generalized vitiligo may share common genetic aetiologic links with other autoimmune diseases, and the genetic component of familial generalized vitiligo is stronger.

Association of HLA haplotype with alopecia areata in Chinese Hans.

BACKGROUND: Some studies have shown discrepancies in human leucocyte antigen (HLA) associated with alopecia areata (AA) between different ethnic populations. OBJECTIVE: To investigate whether HLA-I, -DQA1 and -DQB1 alleles and the HLA haplotype are associated with AA, and the correlation between the HLA haplotype profile, age of onset and severity of AA in Chinese Hans. METHODS: The polymerase chain reaction-sequence specific primer (PCR-SSP) method was used to analyse the frequencies of HLA class I, -DQA1 and -DQB1 alleles in 192 patients with AA and 252 controls in Chinese Hans. The linkage disequilibrium was calculated using the 2 x 2 table. RESULTS: The 24 two-locus haplotypes [including A*02-B*18, A*02-B*27, A*02-B*52, A*02-Cw*0704, A*02-DQA1*0104, A*02-DQB1*0604, A*02-DQB1*0606, B*18-Cw*0704, B*18-DQA1*0104, B*18-DQA1*0302, B*18-DQB1*0606, B*27-Cw*0704, B*27-DQA1*0104, B*27-DQA1*0302, B*52-Cw*0704, B*52-DQA1*0104, B*52-DQA1*0302, B52-DQB1*0606, Cw*0704-DQA1*0104, Cw*0704-DQA1*0302, Cw*0704-DQB1*0606, DQA1*0104-DQB1*0604, DQA1*0104-DQB1*0606, DQA1*0302-DQB1*0606 (P<0.05)] were associated with AA, while eight extended haplotypes (A*02-B*18-DQA1*0104, A*02-B*27-DQA1*0104, A*02-B*52-DQA1*0104, A*02-B*52-DQA1*0302, A*02-B*52-DQB1*0606, B*52-Cw*0704-DQA1*0104, B*52-Cw*0704-DQA1*0302, A*02-B*52-DQA1*0302-DQB1*0606) were found to be related to AA in Chinese Hans. Through stratified analysis, we found that the extended haplotype B*52-Cw*0704-DQA1*0302 was related to early onset of AA, and no haplotype was only associated with severe AA. CONCLUSION: This is the first detailed report to elucidate HLA haplotypes associated with AA and that demonstrates the significant HLA haplotypes in Chinese Hans AA. The haplotype B*52-Cw*0704-DQA1*0302 was identified to be related to early onset of AA. Our results provide some information for future research on predisposing genes in HLA regions in Chinese Hans.

Alopecia areata in children: a clinical profile.

Alopecia areata (AA) is prevalent among children in Kuwait. In this prospective survey we studied 215 children with AA to determine their clinical and epidemiologic features. Ninety-seven percent of the children were of Arab ancestry. Girls outnumbered boys by a 2.5:1 ratio. The peak age of onset was seen between 2 and 6 years of age with a mean age of onset at 5.7 +/- 2.8 years. A majority of the patients (80.5%) had mild disease and extensive disease (more than 50% hair loss) was seen in 13% of the children. A positive family history of AA was obtained in 51.6% of cases and nail changes were seen in 26.5% of the children. The age of onset, a positive family history of AA, and associated atopic disorders were observed to have no influence on the extent and severity of the disease. The results were compared with those reported elsewhere for this age group.

Evaluation of thyroid function in north Indians with alopecia areata: response to intravenous injection of 100 micrograms thyrotropin releasing hormone (TRH).

There is a lack of agreement on the overall prevalence of thyroid disease and thyroid function abnormalities in alopecia areata. Only one study is available from the Indian subcontinent. All patients with alopecia areata attending a dermatology outpatient clinic between 1983 and 1997 were screened for the presence of clinical thyroid disease. Sixty-two consecutive patients during the year 1994 were evaluated in detail for thyroid functions by measuring T3, T4, TSH levels and testing for antithyroid and antimicrosomal antibodies. Twenty-two patients randomly selected from the above-mentioned sixty two were studied for TSH response to intravenous injection of 100 micrograms TRH at -20, 0 and 20, 60, and 120 minutes after TRH injection. Thyroid disease was clinically evident in 16 (0.85%) of the 1700 patients with alopecia areata seen over the last fifteen years. All sixty-two patients evaluated for thyroid functions were clinically euthyroid. Seven (11.3%) out of these 62 patients had abnormal thyroid hormone levels. Antithyroid and antimicrosomal antibodies were found in five patients; all five had abnormalities in thyroid function. TSH response to TRH was suggestive of hypothyroidism in 4 (18%) of the 22 patients studied. Manifest thyroid disease is infrequently associated with alopecia areata. Abnormalities in thyroid functional status were more frequent; they were found in 7 (11.3%) out of 62 patients. TSH response to intravenous TRH was abnormal in an even higher proportion [4 (18%) out of 22 patients]. There was no apparent correlation with duration or type of alopecia areata.