Alopecia areata in Korea (1982-1994)

Bilateral Association Between Atopic Dermatitis® and Alopecia Areata: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to explore the association between atopic Dermatitis® (AD) and alopecia areata (AA). A comprehensive search was conducted in PubMed, Embase, Cochrane, and Web of Science from the inception of each database to November 10, 2022 for relevant studies. As there is a potential bilateral association between the 2 diseases, we assessed the prevalence/incidence of AA in patients with AD and the prevalence/incidence of AD in patients with AA. A total of 29 studies involving 11,233,448 participants were included in this analysis. AA was the exposure factor in 23 studies, AD in 7 studies, and both in 1 study. The meta-analysis revealed that the prevalence of AD was 11.2% (7.7%-15.1%) in patients with AA, and the prevalence of AA was 3.2% (95% confidence interval [CI]: 0.0%-11.5%) in patients with AD. The incidence of AD in AA patients was found to vary with age (P = 0.07). Based on 7 studies, there was a significant association between AD and AA when AA was the exposure factor [odds ratio, OR, = 4.537 (95% CI: 2.409-8.544)]; based on 10 studies, there was also a significant association between AD and AA when AD was the exposure factor [OR = 2.643 (95% CI: 1.737-3.995)]. In conclusion, this meta-analysis demonstrated the 2-way association between AD and AA, providing a clinical reference for disease prevention and control.

Comorbid Conditions Associated with Alopecia Areata: A Systematic Review and Meta-analysis

BACKGROUND

Alopecia areata (AA) is a complex autoimmune condition resulting in nonscarring hair loss. In recent years, many studies have provided new evidence on comorbid diseases present in patients with AA. However, some studies have conflicting results, and analyses conducting a comprehensive approach are lacking.

OBJECTIVE

The aim of our study was to provide an updated systematic review and meta-analysis of medical comorbidities associated with AA.

METHODS

We searched PubMed, Embase, and Web of Science for case-control, cross-sectional, and cohort studies investigating medical comorbidities in AA published from inception through 1 February 2023.

RESULTS

We screened 3428 abstracts and titles and reviewed 345 full text articles for eligibility. Ultimately, 102 studies were analyzed, comprising 680,823 patients with AA and 72,011,041 healthy controls. Almost all included studies (100 of 102 studies) were of satisfactory to high quality (Newcastle-Ottawa scale score ≥ 4). Among patients with AA, comorbidities with the highest odds ratios (OR) compared with healthy controls and data available from more than one study included vitamin D deficiency (OR 10.13, 95% CI 4.24-24.20), systemic lupus erythematous (OR 5.53, 95% CI 3.31-9.23), vitiligo (OR 5.30, 95% CI 1.86-15.10), metabolic syndrome (OR 5.03, 95% CI 4.18-6.06), and Hashimoto's thyroiditis (OR 4.31, 95% CI 2.51-7.40). AA may be a protective factor for certain disorders, for which the AA group had lower odds compared with healthy controls, such as irritable bowel syndrome (OR 0.38, 95% CI 0.14-0.99) and colorectal cancer (OR 0.61, 95% CI 0.42-0.89).

CONCLUSION

These findings corroborate and contextualize the risks across comorbidities for patients with AA. Further work should be done to identify the underlying pathophysiology and understand appropriate screening criteria.

Inverse correlation between vitamin D and CRP levels in alopecia areata: A pilot study

INTRODUCTION

Alopecia areata (AA) is an autoimmune non-scarring hair loss. The role of micronutrients such as iron, zinc, and vitamins, especially vitamin D, on the natural hair cycle is well defined in literature. This study aims to evaluate the correlation between vitamin D and CRP levels in patients with alopecia areata.

METHODS

This cross-sectional study was performed from beginning of October 2020 until end of December 2021. Alopecia areata patients over 18 years of age gave their written consent to participate in the study. The severity of the patients' disease was assessed using the Severity of Alopecia Tool. Serum vitamin D and CRP levels were measured and CBC and LFT were also performed.

RESULTS

There were significant differences between the patients with the localized form of AA and its universal form in the following variables: Vitamin D levels, SALT score, WBC, ALKP, and CRP. There was also a significant inverse correlation between CRP and vitamin D levels (p < 0.0001).

CONCLUSION

Vitamin D deficiency is associated with higher CRP levels, and patients with low serum vitamin D and high CRP levels are at a higher risk of developing the universalis form of AA; therefore, these patients should undergo more aggressive treatments.

Demographic and Clinical Features of 1,641 Patients with Alopecia Areata, Alopecia Totalis, and Alopecia Universalis: A Single-Center Retrospective Study

Background/Aim

Alopecia areata (AA) is a common autoimmune hair disorder which is characterized by noncicatricial hair loss. AA commonly presents with localized patches on the scalp and face but may affect any hair-bearing region of the body leading to even more generalized involvement. AA may affect any age group, gender, and race. The current study investigates the demographic characteristics of the patients with AA and subgroups of AA including alopecia totalis (AT) and alopecia universalis (AU) and the prevalence of disease, sex, and age distribution and seasonal variation retrospectively in a tertiary dermatology clinic in Turkey.

Materials and Methods

In this retrospective, cross-sectional study, 1,641 patients diagnosed with AA, AT, and AU in the dermatology clinic of a public university hospital were included. The dermatology outpatient database was reviewed retrospectively. The diagnosis of AA was based on patient history, clinical examinations, and histopathologic findings.

Results

Fifty-four thousand one hundred sixty-eight patients were admitted to our outpatient clinic in 4 years time, and 1,641 were diagnosed as having AA, AT, and AU. One thousand three hundred ninety-two patients (84.8%) had AA, 81 (4.9%) had AT, and 168 (10.2%) had AU. Among the 1,641 patients included in the study, 877 were females (53.4%) and 764 were males (46.6%). The mean age was 29.86 ± 14.48 years in AA, 29.50 ± 16.18 in AT, and 32.81 ± 14.48 in AU; 77.4, 72.8, and 68.5% of patients were aged under 40 years in AA, AT, and AU. There was no statistically significant difference in seasonal presentation times.

Conclusion

AA is affecting approximately 2% of the general population without any sex, race, or age group predilection. In this study, we found a lower prevalence of AA in the pediatric age group in comparison with adults. This finding may support the hypothesis of the increasing prevalence of AA over time. The higher ratio of AA regarding this study may support that the frequency of AA and subtypes varies between regions.

Assessment of treatment efficacy of diphenylcyclopropenone (DPCP) for alopecia areata

Background/aim

Alopecia areata (AA) is an inflammatory disease with a genetic and autoimmune basis. Herein, it was aimed to study the efficacy and safety of an immunomodulatory therapeutic agent, diphenylcyclopropenone, while manifesting its association with histopathological features, prognostic factors, and side effects.

Materials and methods

In this retrospective study, 98 patients (60 males, 38 females) with alopecia, who were referred to the Hair Disease Polyclinic at the Department of Dermatology, between 2011 and 2015, were included. Together with medical histories and dermatological examinations, a skin biopsy for histopathological examination was conducted for all of the patients prior to therapy. Therapeutic success was evaluated on the basis of the hair regrowth percentage.

Results

Regarding the overall treatment success, 33 (34%) patients had complete response, 16 (16%) had partial response (between 50% and 99%), 27 (28%) had minimal response (between 1% and 49%), and 22 (22%) were nonresponders. Both sexs were equally represented in the outcome.

Conclusions

There was a significant relation between the severity of alopecia and the treatment outcome (P = 0.038). Patients with AA had significantly better response when compared to those with alopecia totalis and universalis. There was no statistically significant relation with other parameters, such as disease duration, age, sex, atopy history, age of onset, and histopathological features.

Prevalence and Clinical Characteristics of Alopecia Areata at a Tertiary Care Center in Saudi Arabia

Results

A total of 216 patients with AA were included. The overall prevalence of AA was approximately 2.3%. The mean disease duration at the time of presentation was 2 months while the mean age of onset was 25.61 years. The most common type of AA in both adult and pediatric groups was the patchy type involving the scalp. Comorbid diseases were found in 32.41% of patients. Common associated conditions included hypothyroidism, diabetes mellitus, and atopic diseases.

Conclusion

The overall prevalence of AA among a population of Saudi patients is 2.3%. AA prevalence is higher in pediatrics than adults. Common comorbid conditions include hypothyroidism, diabetes mellitus, and atopic diseases.

Monotherapy for Alopecia Areata: A Systematic Review and Network Meta-Analysis

BACKGROUND

There are many treatments available for alopecia areata; however, none are approved by the US Food and Drug Administration. Thus, there is clinician benefit in efficacy comparison.

METHODS

A network meta-analysis was used to create direct and indirect comparisons of alopecia areata studies in addition to an inconsistency analysis, risk of bias, and quality of evidence assessment.

RESULTS

For mild disease, intralesional corticosteroids were ranked the most likely to produce a response at 78.9% according to SUCRA (surface under the cumulative ranking curve) followed by topical corticosteroids (67.9%), prostaglandin analogs (67.1%), diphenylcyclopropenone (DPCP, 63.4%), topical minoxidil (61.2%), and squaric acid dibutylester (SADBE, 35.0%). In contrast, for moderate to severe disease (>50% scalp hair loss), DPCP was the top-ranked treatment (87.9%), followed by laser (77.9%), topical minoxidil (55.5%), topical corticosteroids (50.1%), SADBE (49.7%), and topical tofacitinib (47.6%). There were insufficient eligible trials to include oral tofacitinib in the network.

CONCLUSION

Statistically significant evidence is presented for the use of intralesional and topical corticosteroids for treatment of mild disease and DPCP, laser, SADBE, topical minoxidil and topical corticosteroids for moderate to severe disease. Further controlled trials are required to analyze the relative efficacy of oral tofacitinib.

The Immunological Association between Alopecia Areata and Respiratory Diseases: A Systematic Review

Background

While alopecia areata (AA) has been associated with atopy, the immunological relationship is unclear, with the association of specific atopic and systemic respiratory diseases not established. The relationship between T-helper (Th)1-mediated AA and Th2-mediated atopy challenges the conventional Th1/Th2 paradigm of autoimmune disease categorization.

Objectives

To determine the association between AA and atopic respiratory diseases in adults and children, and respiratory diseases in general.

Method

All primary literature, excluding case reports, were identified within PubMed/MEDLINE, CINAHL, and Web of Science in May 2018 using the following search terms: "(alopecia OR hair loss) AND (respiratory OR pulmonary OR lungs OR asthma OR rhinitis OR bronchitis OR COPD OR atopy OR atopic)." Information from 32 articles meeting the inclusion and exclusion criteria was reviewed.

Results

Among the 32 articles identified for inclusion, the prevalence of AA was more strongly associated with allergic rhinitis compared to asthma among pediatric and adult populations. While a significant association was identified between AA, allergic rhinitis, and a late age of onset, the association of AA and asthma remains controversial despite asthma's prevalence among AA patients. No significant difference was identified with regard to the association of AA and non-atopic respiratory diseases between adult and pediatric patients.

Conclusions

Adult and pediatric patients with AA warrant further workup for atopic respiratory diseases such as allergic rhinitis. AA may have an underlying Th2-mediated immunological component, which supports its association with atopic respiratory diseases and provides a new avenue for targeted therapies in select cases.

Alopecia areata

Alopecia areata is an autoimmune disorder characterized by transient, non-scarring hair loss and preservation of the hair follicle. Hair loss can take many forms ranging from loss in well-defined patches to diffuse or total hair loss, which can affect all hair-bearing sites. Patchy alopecia areata affecting the scalp is the most common type. Alopecia areata affects nearly 2% of the general population at some point during their lifetime. Skin biopsies of affected skin show a lymphocytic infiltrate in and around the bulb or the lower part of the hair follicle in the anagen (hair growth) phase. A breakdown of immune privilege of the hair follicle is thought to be an important driver of alopecia areata. Genetic studies in patients and mouse models have shown that alopecia areata is a complex, polygenic disease. Several genetic susceptibility loci were identified to be associated with signalling pathways that are important to hair follicle cycling and development. Alopecia areata is usually diagnosed based on clinical manifestations, but dermoscopy and histopathology can be helpful. Alopecia areata is difficult to manage medically, but recent advances in understanding the molecular mechanisms have revealed new treatments and the possibility of remission in the near future.

Treating Alopecia Areata: Current Practices Versus New Directions

Alopecia areata (AA) is non-scarring hair loss resulting from an autoimmune disorder. Severity varies from patchy hair loss that often spontaneously resolves to severe and chronic cases that can progress to total loss of scalp and body hair. Many treatments are available; however, the efficacy of these treatments has not been confirmed, especially in severe cases, and relapse rates are high. First-line treatment often includes corticosteroids such as intralesional or topical steroids for mild cases and systemic steroids or topical immunotherapy with diphenylcyclopropenone or squaric acid dibutylester in severe cases. Minoxidil and bimatoprost may also be recommended, usually in combination with another treatment. Ongoing research and new insights into mechanisms have led to proposals of innovative therapies. New directions include biologics targeting immune response as well as lasers and autologous platelet-rich plasma therapy. Preliminary data are encouraging, and it is hoped this research will translate into new options for the treatment of AA in the near future.

Morphological and morphometric study of the androgenetic alopecic scalp using two- and three-dimensional analysis comparing regional differences

BACKGROUND

Androgenetic (male-type) alopecia (AGA) is caused by genetic and androgenetic effects. The progression of baldness results in smaller hair papillae, thinner hair and a shortened hair cycle. Alopecia occurs mainly in the frontal region and, to a lesser extent, in the occipital region.

OBJECTIVES

The morphological differences in the hair follicular units between the alopecic frontal scalp and the vertex and occipital regions were compared using cross-sectional histology and three-dimensional reconstruction.

METHODS

Skin specimens were obtained from the frontal, vertex and occipital regions of 24 male human cadavers with fully progressed AGA, and from the frontal region of 32 normal cadaveric scalps. These specimens were fixed, processed using routine histological methods, serially sectioned at a thickness of 10 μm and then stained with Masson's trichrome. The serial sections were reconstructed three-dimensionally using 'Reconstruct' software.

RESULTS

The ratios between the numbers of terminal and vellus hairs in the frontal and occipital regions in the AGA scalps were 0·2 : 1 and 3·5 : 1, respectively. Almost all of the hair follicles in the frontal region were vellus hair follicles. The sebaceous gland and arrector pili muscle were larger in the frontal region than in the occipital region.

CONCLUSIONS

The morphology of the AGA scalp has been characterized. The terminal-to-vellus hair ratio in the occipital (normal) region was different from that in the frontal (alopecic) region. Moreover, sebaceous glands were larger in the frontal alopecic region than in the occipital region. These larger glands may be associated with other dermatological pathologies, such as seborrhoeic dermatitis.

Development of autoimmune hair loss disease alopecia areata is associated with cardiac dysfunction in C3H/HeJ mice

Alopecia areata (AA) is a chronic autoimmune hair loss disease that affects several million men, women and children worldwide. Previous studies have suggested a link between autoimmunity, stress hormones, and increased cardiovascular disease risk. In the current study, histology, immunohistology, quantitative PCR (qPCR) and ELISAs were used to assess heart health in the C3H/HeJ mouse model for AA and heart tissue response to adrenocorticotropic hormone (ACTH) exposure. Mice with AA exhibited both atrial and ventricular hypertrophy, and increased collagen deposition compared to normal-haired littermates. QPCR revealed significant increases in Il18 (4.6-fold), IL18 receptor-1 (Il18r1; 2.8-fold) and IL18 binding protein (Il18bp; 5.2-fold) in AA hearts. Time course studies revealed a trend towards decreased Il18 in acute AA compared to controls while Il18r1, Il18bp and Casp1 showed similar trends to those of chronic AA affected mice. Immunohistochemistry showed localization of IL18 in chronic AA mouse atria. ELISA indicated cardiac troponin-I (cTnI) was elevated in the serum and significantly increased in AA heart tissue. Cultures of heart atria revealed differential gene expression between AA and control mice in response to ACTH. ACTH treatment induced significant increase in cTnI release into the culture medium in a dose-dependent manner for both AA and control mice. In conclusion, murine AA is associated with structural, biochemical, and gene expression changes consistent with cardiac hypertrophy in response to ACTH exposure.

Recombinant human hepatitis B vaccine initiating alopecia areata: testing the hypothesis using the C3H/HeJ mouse model

Untoward effects of human vaccines suggest that recombinant hepatitis B vaccine may induce alopecia areata (AA) in some patients. Similar untoward immunological effects may also account for AA-like diseases in domestic species. In this study, the C3H/HeJ spontaneous adult onset AA mouse model was used to test the role, if any, of recombinant hepatitis B vaccine on the initiation or activation of AA. Initial experiments demonstrated no effect on induction of AA in young adult female C3H/HeJ mice (P = 0.5689). By contrast, older females, those at the age when AA first begins to appear in this strain, had a significant increase (P = 0.0264) in the time of onset of AA, suggesting that the vaccine may initiate disease in mice predisposed to AA. However, larger vaccine trials, which included diphtheria and tetanus toxoids as additional controls, did not support these initial result findings and suggest that AA associated with vaccination may be within the normal background levels of the given population.

Alopecia areata in Turkey: demographic and clinical features

BACKGROUND

Alopecia areata is a complex genetic disease with still many unknown aspects, and many studies have been tried to find some clues about it.

OBJECTIVE

We aimed to investigate the demographic and clinical characteristics of alopecia areata in Turkish patients.

METHODS

Demographic data, localization, attack number in addition to some parameters such as disease duration, severity, age of onset, family history and ophiasis pattern were evaluated in 539 alopecia areata patients.

RESULTS

The male to female ratio was 1.6:1. Occipital and beard-moustache areas were mostly affected. Positive family history was noticed in 24.1% of the patients. The age of onset was earlier in women than in men (P = 0.04). Severe forms showed more persistent (> or = 1 year) disease duration (P = 0.00). Ophiasis was more common in severe, long duration (> or = 1 year) and early onset (< or = 18 years) disease (P = 0.00 for all parameters). Childhood alopecia areata (< or = 18 years) was also associated with long duration of the disease (P = 0.016) and positive family history (P = 0.008) when compared with adult onset (> 18 years) alopecia areata.

Alopecia areata universalis elicited during treatment with adalimumab

Adalimumab is a fully humanized recombinant anti-tumour-necrosis-factor (TNF-alpha) monoclonal antibody which has been approved for rheumatoid arthritis, active ankylosing spondylitis, psoriatic arthritis and Crohn's disease. We report a case of alopecia areata (AA) universalis occurring 6 months after administration of adalimumab monotherapy in a patient with a long-standing history of psoriatic arthritis and psoriasis. The diagnosis was confirmed by a scalp biopsy which showed a peribulbar infiltrate of both CD4+ and CD8+ T cells, CD1a+ dendritic cells as well as CD68+ and CD163+ macrophages. In addition, immunofluorescence staining for TNF-alpha was found in the mononuclear cell infiltrate. This case suggests a complex role of TNF-alpha in the induction of AA.

Familial aggregation of alopecia areata

BACKGROUND

Familial aggregation of alopecia areata (AA) has been previously described, but systematic studies with information obtained directly from family members have yet to be undertaken.

OBJECTIVE

We sought to study the pattern of familial aggregation of AA by assessing the affection status of patients' relatives. The study included 206 index patients with a total of 1029 first-degree and 2625 second-degree relatives.

METHODS

First-degree relatives were directly interviewed, whereas information on second-degree relatives was obtained by interviewing the index patients and their first-degree relatives.

RESULTS

Estimated lifetime risks were 7.1% in siblings, 7.8% in parents, and 5.7% in offspring. The risk in second-degree relatives was slightly higher than the reported population risk. Age at onset in index patients and first-degree relatives was significantly correlated.

LIMITATIONS

Using patients drawn from specialized hair clinics may have produced results showing a higher proportion of early onset and severe cases.

CONCLUSION

The familial aggregation of AA supports the role of genetic factors in the development of the disease. In addition, our data indicate genetic factors might contribute to the age at onset of AA.

Autoimmune hair loss induced by alloantigen in C57BL/6 mice

Exponentially growing Meth-A cells expressing H-2K(d).D (d) antigen were found to induce alopecia when injected intraperitoneally into normal C57BL/6 mice, which express the H-2K(b).D (b) antigen. However, the capacity to induce alopecia disappeared when Meth-A cells were treated with K252a, which inhibits protein kinases. Histologically, skin in affected areas showed dense mononuclear cell infiltration and a focal foreign-body giant-cell reaction in hair follicles. The subtyping of lymphocytes in peripheral blood demonstrated a significant difference between normal mice and Meth-A cell-injected mice. To further examine the mechanism by which the alloantigen induces alopecia, lymphocytes isolated from the peripheral blood of normal C57BL/6 mice were cultured in medium containing Meth-A cell homogenate, phytohemagglutinin (PHA) and recombinant mouse interleukin-2 (rm IL-2), and intravenously injected into normal C57BL/6 mice. The adoptive transfer of the lymphocytes induced alopecia in a similar way. These findings suggest that the protein kinase-modulated alloantigen induces alopecia by disturbing the immunological homeostasis, and that lymphokine-activated killer cells play an important role in induction of alopecia by cross-reacting with hair follicles.

Role of the autoimmune regulator (AIRE) gene in alopecia areata: strong association of a potentially functional AIRE polymorphism with alopecia universalis

Alopecia areata is characterized by a reversible form of patchy or complete hair loss associated with T-cell infiltration of hair follicles. The lifetime disease risk of approximately 1.4% in the general population is increased to more than 30% in autoimmune polyendocrinopathy candidiasis ectodermal dysplasia syndrome (APECED), a recessive condition resulting from a mutation of the autoimmune regulator (AIRE) gene on chromosome 21q22.3. Aire protein is thought to have transcriptional regulatory activity but its role is not well defined at present. In this study, we have examined the possible involvement of AIRE in the pathogenesis of alopecia areata. On screening the AIRE coding sequence, we identified 20 variants. Two of these at positions, G961C and T1029C, give rise to amino acid changes, S278R and V301A, located in the DNA-binding segment (SAND) and PHD1 zinc finger motif, respectively. We found no difference in the frequency of the AIRE T1029C polymorphism between the control and patient groups. We genotyped 202 alopecia areata patients and 175 matched Caucasian controls for the AIRE G961C alleles. The frequency of the rare allele (961G) was 0.08 in the controls and there was a significant increase to 0.13 in alopecia areata overall and 0.20 in severe disease (alopecia universalis). We found no association between the AIRE G961G variant and mild (patchy) alopecia areata or alopecia totalis. However, the AIRE 961G allele is a potent risk factor (> 3) for the severest form of alopecia areata, and for disease of early age at onset (at 30 years). The change from serine to arginine in the SAND domain of AIRE protein may have a significant effect on AIRE DNA-binding activity. Moreover, our results could provide a rational explanation of the unusually high frequency of AA in APECED patients, supporting the concept of AA as an autoimmune disease.

Langerhans cells that express matrix metalloproteinase 9 increase in human dermis during sensitization to diphenylcyclopropenone in patients with alopecia areata

BACKGROUND

We know little of the initial events during the sensitization phase of contact allergy in humans. Alopecia areata (AA), a disease of unknown pathogenesis characterized by patchy hair loss, may be treated by inducing contact allergy to diphenylcyclopropenone (DPC), later followed by its topical application.

OBJECTIVES

To learn more about the initial events during sensitization in human skin, we studied the early events during induction of contact allergy to DPC in patients with AA.

METHODS

DPC 2% and sodium lauryl sulphate (SLS) 4% were applied on the backs of eight patients with AA. Punch biopsies were taken 6 and 24 h after application. The biopsies were snap-frozen and cryostat sections were evaluated with immunohistochemistry using antibodies against CD1a, HLA-DR, CD3, CD54 and matrix metalloproteinase 9 (MMP-9).

RESULTS

After 24 h all subjects exhibited erythema on the DPC-treated areas. Histological evaluation of biopsies from these areas showed hydropic degeneration and a significantly increased number of MMP-9+ cells in the dermis (P < 0.0005). The MMP-9+ cells were identified with double immunofluorescence staining as CD1a + Langerhans cells. The expression of the other markers studied remained unaltered irrespective of treatment, including treatment with SLS.

CONCLUSIONS

Our findings show that DPC induces an irritant reaction leading to an increased number of MMP-9+ CD1a+ cells in the dermis during the initial phase of sensitization.

The therapeutic use of topical contact sensitizers in benign dermatoses

Topical therapy using contact sensitizers has been practised since the 1960s to treat conditions associated with an altered immunological state. Dinitrochlorobenzene, squaric acid dibutyl ester and diphencyprone are most commonly employed in the therapy of alopecia areata and viral warts. Few dermatology departments in the U.K. provide such treatment. This systematic review discusses the various contact sensitizers used for topical immunotherapy, the methodology of treatment, factors influencing efficacy and likely adverse effects.

Colocalization of alopecia areata and vitiligo

We report an 18-year-old woman who had a 4-month history of colocalization of alopecia areata and vitiligo, principally on the occipital portion of the scalp.

Efficacy of topical sensitizers in the treatment of alopecia areata

It has been more than 2 decades since the first report of the use of dinitrochlorobenzene to induce hair growth in 2 patients with alopecia areata. Other topical sensitizers, namely squaric acid dibutylester and diphenylcyclopropenone, have been used with variable success. This article reviews the efficacy and safety of the use of topical sensitizers in the treatment of alopecia areata.