Chemical leukoderma: An insight of pathophysiology and contributing factors

Chemical leukoderma, or chemical-based vitiligo, is a dermal disease triggered by exposure to chemicals and characterized by the emergence of depigmentation or hypopigmentation of the skin. The etiology of this condition is associated with exposure to various chemical substances present in both occupational and non-occupational settings. The precise mechanism that underlies chemical leukoderma remains elusive and is believed to result from the demise of melanocytes, which are responsible for producing skin pigments. This condition has gained particular prominence in developing countries like India. An interesting connection between chemical leukoderma and vitiligo has been identified; studies suggest that exposure to many household chemicals, which are derivatives of phenols and catechol, may serve as a primary etiological factor for the condition. Similar to autoimmune diseases, its pathogenesis involves contributions from both genetic and environmental factors. Furthermore, over the last few decades, various studies have demonstrated that exposure to chemicals plays a crucial role in initiating and progressing chemical leukoderma, including cases stemming from occupational exposure.

Exposome Impact on Nail Health

Background

The nail unit is a complex system with various components, each serving distinct functions. The exposome, encompassing external and internal factors such as UV radiation, air pollution, dietary habits, and cosmetic product usage, substantially influences nail health and can lead to premature nail aging.

Summary

Internal and external exposomal factors can impact differently on nail health, inducing a variety of different clinical conditions. Effective therapeutic strategies exist, but a comprehensive understanding of how the exposome affects nails is lacking. This article aims to bridge this knowledge gap by exploring the relationship between the exposome and nail health, emphasizing it as a central focus of our analysis.

Key Messages

(1) The exposome, comprising various external and internal factors, may significantly influence nail health negatively, leading to premature nail aging. (2) Different nail conditions may arise due to the exposomal influence on nails. (3) Understanding the exposome's impact on nail health is crucial for developing solutions to mitigate negative effects and improve overall nail well-being.

ViCEKb: Vitiligo-linked Chemical Exposome Knowledgebase

Vitiligo is a complex disease wherein the environmental factors, in conjunction with the underlying genetic predispositions, trigger the autoimmune destruction of melanocytes, ultimately leading to depigmented patches on the skin. While genetic factors have been extensively studied, the knowledge on environmental triggers remains sparse and less understood. To address this knowledge gap, we present the first comprehensive knowledgebase of vitiligo-triggering chemicals namely, Vitiligo-linked Chemical Exposome Knowledgebase (ViCEKb). ViCEKb involves an extensive and systematic manual effort in curation of published literature and subsequent compilation of 113 unique chemical triggers of vitiligo. ViCEKb standardizes various chemical information, and categorizes the chemicals based on their evidences and sources of exposure. Importantly, ViCEKb contains a wide range of metrics necessary for different toxicological evaluations. Notably, we observed that ViCEKb chemicals are present in a variety of consumer products. For instance, Propyl gallate is present as a fragrance substance in various household products, and Flutamide is used in medication to treat prostate cancer. These two chemicals have the highest level of evidence in ViCEKb, but are not regulated for their skin sensitizing effects. Furthermore, an extensive cheminformatics-based investigation revealed that ViCEKb chemical space is structurally diverse and comprises unique chemical scaffolds in comparison with skin specific regulatory lists. For example, Neomycin and 2,3,5-Triglycidyl-4-aminophenol have unique chemical scaffolds and the highest level of evidence in ViCEKb, but are not regulated for their skin sensitizing effects. Finally, a transcriptomics-based analysis of ViCEKb chemical perturbations in skin cell samples highlighted the commonality in their linked biological processes. Overall, we present the first comprehensive effort in compilation and exploration of various chemical triggers of vitiligo. We believe such a resource will enable in deciphering the complex etiology of vitiligo and aid in the characterization of human chemical exposome. ViCEKb is freely available for academic research at: https://cb.imsc.res.in/vicekb.

Cigarette smoking is an independent risk factor for developing vitiligo on the hands

BACKGROUND

Vitiligo presents with varying clinical features based on the type and location. Treatment tends to be more effective on the face, neck, trunk, and mid-extremities, while the lips and distal extremities may be more resistant. Vitiligo in frequently exposed areas such as the face, arms, legs, and hands is typically associated with a lower Dermatology Life Quality Index.

OBJECTIVES

We aimed to identify the characteristics and potential causes of vitiligo in challenging-to-treat regions, with particular focus on the hands.

METHODS

We analyzed the clinical data of 337 patients with generalized vitiligo who visited our hospital between 2016 and 2022. For this study, we focused on patients with non-segmental vitiligo (NSV) specifically on their hands. Of the 337 patients, 248 had NSV and 89 had segmental vitiligo; 119 (47%) of those with NSV had vitiligo on their hands. Logistic regression models were applied to identify factors the factors linked to hand vitiligo, such as age, sex, duration of the condition, and smoking and alcohol history.

RESULTS AND CONCLUSIONS

We developed a model to predict the risk of hand vitiligo using several factors. Among the factors analyzed, only smoking history was significantly associated with an increased risk (odds ratio: 3.13). In addition, we used clinical photography to evaluate color-graded frequency heat maps comprising 528 pixels. Vitiligo in nonsmokers widely distributed over the hand, predominantly the fingertips and joints, whereas vitiligo in smokers tended to be distributed mostly at the fingertips.

Fentanyl transdermal patches induced chemical leucoderma

Chemical leucoderma is defined as hypopigmentation or vitiligo-like hypomelanosis caused by repeated chemical exposure, and the diagnosis can be made clinically. Chemical leucoderma induced by fentanyl transdermal patches is rare. This case report involves a 53-year-old man with chronic back pain caused by herniated nucleus pulposus at the L4-L5 level. The patient had used fentanyl transdermal patches for about 2 years. Depigmented lesions were observed in the areas where fentanyl transdermal patches had been applied. Chemical leucoderma was the most likely diagnosis. There remains a debate regarding whether there is a fentanyl dose-response relationship and whether the duration of exposure is relevant. Spontaneous repigmentation may occur after discontinuing the chemical exposure, and follow-ups are recommended to monitor whether spontaneous repigmentation occurs. Additionally, several treatment options have been proposed as specific treatments for chemical leucoderma, including psoralens, corticosteroids, calcineurin inhibitors, immunosuppressive agents and phototherapy.

Dermatological adverse effects of hair dye use: A narrative review

Hair dyeing is a popular practice dating back to ancient Egyptian times. Initially, hair dye use was restricted to concealing grey and white hairs of the elderly population. However, in recent times, its use is common among the younger generation as a fashion statement. Hair dye contact dermatitis is a common dermatological condition encountered by dermatologists. It is a delayed type of hypersensitivity reaction that commonly affects the scalp and the vicinity of hair line and neck. Para-phenylenediamine (PPD), a synthetic aromatic amine is the most common allergen specifically implicated in hair dye contact dermatitis. Para-phenylenediamine was announced as the allergen of the year in 2006 by the American Contact Dermatitis Society. Contact allergy to para-phenylenediamine can occur in 0.1-2.3% of the general population. Epicutaneous patch testing is the gold standard test for the diagnosis of hair dye contact dermatitis. However, para-phenylenediamine carries a risk of cross-sensitivity and co-sensitization to other allergens. Apart from contact dermatitis, hair dye use is also associated with various other cutaneous adverse effects such as pigmentary changes, hair loss, skin malignancies and autoimmune disorders. Due to the various adverse effects associated with hair dye use, it is prudent to look for safer alternatives to allergenic hair dyes. In this article, we review the epidemiology, cutaneous and systemic adverse effects associated with hair dye use, patch testing, preventive strategies to minimize the risk of hair dye contact dermatitis, and treatment aspects.

Prevalence of pesticide related occupational diseases among Indonesian vegetable farmers - A collaborative work

Objective

This study was done to understand the prevalence of various occupational diseases including dry eyes, nail dystrophy, and neuropathy related to pesticide exposure in Indonesian local vegetable farmers.

Methods

The data were collected through questionnaires and physical examination involving dermatology, neurology, and ophthalmology domains at Ngablak District, Magelang, Central Java directed to local vegetable farmers. Ocular Surface Disease Index (OSDI) questionnaire and the Schirmer test were used. Analysis was done using descriptive statistics using the Statistical Package for the Social Sciences (SPSS 21.0) and presented in tables.

Results

Inadequate spraying equipment and improper storage of pesticides were found. Out of 105 farmers, 41.9 % experienced occupational skin diseases (OSD). Definite cognitive impairments were found in 3.4 % of subjects but probable in 28.3 % of subjects. Neuropathies were found in 61.7 % of subjects, and dry-eyes syndrome were found in 28.78 % of subjects.

Conclusion

There was a high prevalence of peripheral neuropathy and tremor, dry eyes syndrome in one-third of the population, and the most common skin problem was nail discoloration, with a low incidence of contact dermatitis.

Chemical Vitiligo: A Subset of Vitiligo

Chemical leucoderma, an under-diagnosed common condition often mimicking idiopathic vitiligo, represents an acquired depigmentation induced by repeated exposure to specific chemical compounds in subjects with genetic susceptibility to vitiligo. This has been increasing rapidly in incidence in recent decades in developing countries like India. The term 'chemical vitiligo' was first coined by us to indicate the possible relationship between chemical leucoderma and vitiligo, which has been supported recently by other authors to designate the term 'chemical-induced vitiligo'. The largest case series showed that household chemical exposure was the major etiological factor. Causative chemicals are mostly phenolic and catecholic derivatives. Vitiligo pathogenesis is induced by genetic and environmental factors like many other autoimmune diseases. Innate immunity acts as a bridge between cellular stress and adaptive immunity. Multiple patches are commonly seen; children below 12 years are also affected in good numbers. The most common presence of confetti macules indicates these as characteristic, although not pathognomonic, of chemical leucoderma. Chemical leucoderma has been broadened into 'chemical leucoderma syndrome' with proper staging. The clinical criteria for diagnosis of chemical leucoderma have been specifically outlined. Same pathomechanism of chemical leucoderma might elucidate trigger factors and reasons for progression and chronicity in idiopathic vitiligo. Depigmentation in chemical vitiligo spreads to distant sites, in the same way as generalized idiopathic vitiligo. The study showed that chemical triggering factors played a very significant role in the induction and progression of vitiligo. Thus it should be rational to consider chemical vitiligo not as a separate entity but as a major subset of vitiligo spectrum.

Face and Neck Pigmentary Alterations in Hair Dye Users: A Cross-sectional Study from South India

Background:

Hair dyes are commonly used for the concealment of grey hair in India. The pigmentary alterations produced by hair dyes on the face and neck have not received sufficient attention.

Aims:

To study the pigmentary alterations on the face and neck in hair dye users, and identify possible risk factors associated with the face and neck hyperpigmentation.

Methods:

A hospital-based descriptive cross-sectional study was done on consecutive hair dye users. A detailed history was taken, and a clinical examination was done to record the pigmentary alterations. The patterns, areas affected, the intensity of hyperpigmentation, percentage of the area involved and risk factors were noted.

Results:

One hundred and twenty patients were included in the study. Around 118 (98.3%) patients had hyperpigmentation over face and/or neck: 16 (13.3%) barely perceivable, 40 (33.3%) mild, 44 (36.7%) moderate, and 18 (15%) severe pigmentation. The lateral forehead (106, 88.3%), the helix of the ear (106, 88.3%), central forehead (97, 80.8%), and zygomatic area (92, 76.7%) were the most frequently affected areas in our study. Fourteen patients (11.7%) had depigmented macules on the scalp and/or lips.

Conclusion:

Pigmentary alterations, particularly hyperpigmentation over the upper face and ears are common with the use of hair dyes. The skin type may play a role in the intensity of hyperpigmentation.

Genome-wide association study identifies CDH13 as a susceptibility gene for rhododendrol-induced leukoderma

Racemic RS-4-(4-hydroxyphenyl)-2-butanol (rhododendrol; trade name: Rhododenol [RD]), which is used in topical skin-lightening cosmetics, was unexpectedly reported in Japan to induce leukoderma or vitiligo called RD-induced leukoderma (RIL) after repeated application. To our knowledge, no studies have investigated chemical-induced vitiligo pathogenesis on a genome-wide scale. Here, we conducted a genome-wide association study (GWAS) for 147 cases and 112 controls. CDH13, encoding a glycosylphosphatidylinositol-anchored protein called T-cadherin (T-cad), was identified as the strongest RIL susceptibility gene. RD sensitivity was remarkably increased by T-cad knockdown in cultured normal human melanocytes. Furthermore, we confirmed tyrosinase upregulation and downregulation of the anti-apoptotic molecules (BCL-2 and BCL-XL), suggesting that T-cad is associated with RD via tyrosinase or apoptotic pathway regulation. Finally, monobenzyl ether of hydroquinone sensitivity also tended to increase with T-cad knockdown, suggesting that the T-cad could be a candidate susceptibility gene for RIL and other chemical-induced vitiligo forms. This is the first GWAS for chemical-induced vitiligo, and it could be a useful model for studying the disease's genetic aspects.

Vitiligo: Mechanisms of Pathogenesis and Treatment

Vitiligo is an autoimmune disease of the skin that targets pigment-producing melanocytes and results in patches of depigmentation that are visible as white spots. Recent research studies have yielded a strong mechanistic understanding of this disease. Autoreactive cytotoxic CD8+ T cells engage melanocytes and promote disease progression through the local production of IFN-γ, and IFN-γ-induced chemokines are then secreted from surrounding keratinocytes to further recruit T cells to the skin through a positive-feedback loop. Both topical and systemic treatments that block IFN-γ signaling can effectively reverse vitiligo in humans; however, disease relapse is common after stopping treatments. Autoreactive resident memory T cells are responsible for relapse, and new treatment strategies focus on eliminating these cells to promote long-lasting benefit. Here, we discuss basic, translational, and clinical research studies that provide insight into the pathogenesis of vitiligo, and how this insight has been utilized to create new targeted treatment strategies.

The enigma and challenges of vitiligo pathophysiology and treatment

Vitiligo is the most common acquired pigmentary disorder, which afflicts 0.5%-1% of the world population, and is characterized by depigmented skin patches resulting from melanocyte loss. Vitiligo has a complex etiology and varies in its manifestations, progression, and response to treatment. It presents as an autoimmune disease, evidenced by circulating melanocyte-specific antibodies, and association with other autoimmune diseases. However, autoimmunity may be secondary to the high oxidative stress in vitiligo skin and to intrinsic defects in melanocytes and their microenvironment, which contribute to aberrant stress response, neo-antigenicity, and susceptibility of melanocytes to immune attack and apoptosis. There is also a genetic predisposition to vitiligo, which sensitizes melanocytes to environmental agents, such as phenolic compounds. Currently, there are different treatment modalities for re-pigmenting vitiligo skin. However, when repigmentation is achieved, the major challenge is maintaining the pigmentation, which is lost in 40% of cases. In this review, we present an overview of the clinical aspects of vitiligo, its pathophysiology, the intrinsic defects in melanocytes and their microenvironment, and treatment strategies. Based on lessons from the biology of human melanocytes, we present our perspective of how repigmentation of vitiligo skin can be achieved and sustained.

Dermatoses Occurring after Parlor Procedures

Background:

Cosmetic procedures are on the rise and practiced by all age groups, especially by teenagers. These procedures enhance the individual appearance and confidence levels, but they are not without side effects.

Aims and Objectives:

The aim of this study was to evaluate the side effects occurring after various parlor procedures such as facials, threading, waxing, and laser hair reduction.

Setting and Design:

A prospective study for 12 months in a tertiary hospital.

Materials and Methods:

Patients attending the department of dermatology at a tertiary care hospital for 12 months (July 2018–June 2019) were evaluated for any skin lesions, developed after one of the above parlor procedures. Detailed history, clinical examination, and correlation with the parlor procedure were noted.

Results:

A total of 102 patients were found to have dermatoses after various parlor procedures during the 1-year study period (81 F and 21 M). Acneiform eruptions 26 (25.4%), followed by post-waxing folliculitis 17(16.7%), and hyperpigmentation of face 15 (14.7%) were the most common dermatoses. Molluscum contagiosum, verrucae plana, and tinea faciei were observed in 11, 6, and 3 patients, respectively.

Conclusion:

Side effects are not uncommon after parlor procedures. Awareness of these is necessary and educating the patients is extremely important to avoid these unwanted complications.

Leukoderma induced by rhododendrol is different from leukoderma of vitiligo in pathogenesis: A novel comparative morphological study

BACKGROUND

Rhododendrol (rhododenol), an inhibitor of tyrosinase activity, is used as a skin-whitening component. Many cases of leukoderma after the application have been reported, termed rhododenol-induced leukoderma (RIL). The aim of this study was to clarify the pathogenesis of RIL morphologically through comparison with vitiligo.

METHODS

We examined 14 cases of RIL and 15 cases of vitiligo using routine histopathology and immunohistochemistry. Thirteen cases of RIL, six cases of vitiligo and specimens of the RIL mouse model were evaluated by electron microscopy.

RESULTS

There were common findings in RIL and vitiligo at the light-microscopic level: (a) vacuolar changes in the dermo-epidermal junction, (b) melanophages in the papillary dermis, (c) perifollicular lymphocyte infiltration, (d) loss or decrease of basal melanin pigment and (e) decrease of melanocytes in the lesions. The ultrastructural observations showed specific findings of RIL: (a) remaining melanocytes in depigmented lesions, (b) inhomogeneous melanization in melanocytes and (c) degenerated melanosomes in melanocytes. Some of the findings were observed in a RIL mouse model. Furthermore, it is notable that cell organelles of melanocytes were intact in our RIL cases.

CONCLUSION

Morphological changes of RIL targeting melanosomes in melanocytes without degeneration of organelles reflect the reversible clinical course of most cases.

Acquired disorders with depigmentation: A systematic approach to vitiliginoid conditions

Acquired disorders with depigmentation are commonly encountered by dermatologists and present with a wide differential diagnosis. Vitiligo, the most common disorder of acquired depigmentation, is characterized by well-defined depigmented macules and patches. Other conditions, such as chemical leukoderma, can present with similar findings, and are often easily mistaken for vitiligo. Key clinical features can help differentiate between acquired disorders of depigmentation. The first article in this continuing medical education series focuses on conditions with a vitiligo-like phenotype. Early recognition and adequate treatment of these conditions is critical in providing appropriate prognostication and treatment.

Multispectral Dermatoscopic Features of Chemical Leucoderma with Pigmented Contact Dermatitis

Chemical leukoderma is characterized by pigment loss on constant exposure to chemical agents. Its association with pigmented contact dermatitis is rare. Here, we report a 40-year-old female presenting with depigmented macule with surrounding hyperpigmentation over the upper forehead. We used a multispectral dermatoscope by which decreased pigment network was better visualized with blue light, and gray granular dots were better appreciated with yellow light. Shorter wavelengths delineate epidermal features better whereas longer wavelengths highlight dermal features in multispectral dermatoscopy.

Efficacy and safety of noncultured melanocyte-keratinocyte transplant procedure for vitiligo and other leukodermas: a critical analysis of the evidence

Vitiligo is an acquired pigmentary skin of depigmentation occurring secondary to melanocyte destruction. Vitiligo and other leukodermas have a profound impact on quality of life. Current therapies include medical options, such as phototherapy, topical and systemic corticosteroids, topical calcineurin inhibitors, immunomodulators, and antioxidiants, and surgical options. Surgical options provide melanocytic cells to previously depigmented areas and use either tissue grafting or cellular grafting methods. Topical treatments are often insufficient, and many of the current surgical procedures have shown variable response rates. In this review, we discuss the process of the cellular grafting melanocyte-keratinocyte transplantation procedure (MKTP) and critically analyze its efficacy and safety in the treatment of vitiligo and other leukodermas. PubMed was searched for studies (2001-2017) describing the use of MKTP in patients with vitiligo or other leukodermas. Articles or trials discussing the use of MKTP for these patients were selected for in-depth review. Clinically relevant results regarding efficacy and safety of MKTP in vitiligo and leukoderma patients were analyzed. Numerous trials and case series/reports have demonstrated tolerability and efficacy of MKTP with repigmentation for patients with refractory, stable vitiligo. However, the response rates have been variable, likely influenced by vitiligo type and affected areas. Future research and clinical reporting will provide more insight on which phenotypes may benefit from MKTP.

Chemical-Induced Vitiligo

Chemical-induced depigmentation of the skin has been recognized for more than 75 years, first as an occupational hazard but then extending to those using household commercial products as common as hair dyes. Since their discovery, these chemicals have been used therapeutically in patients with severe vitiligo to depigment their remaining skin and improve their appearance. Because chemical-induced depigmentation is clinically and histologically indistinguishable from nonchemically induced vitiligo, and because these chemicals appear to induce melanocyte autoimmunity, this phenomenon should be known as "chemical-induced vitiligo," rather than less accurate terms that have been previously used.

Chemical leukoderma induced by dimethyl sulfate

Chemical leukoderma occurs due to the toxic effect of a variety of chemical agents. Mechanisms include either destruction or inhibition of melanocytes. We report two male patients (36 and 51 years old) who presented with multiple hypopigmented macules and patches on the neck, wrist, and legs after exposure to dimethyl sulfate in a chemical industry. Physical examination revealed irregular depigmentation macules with sharp edges and clear hyperpigmentation around the lesions. History of repeated exposure to a chemical agent can help the clinical diagnosis of chemical leukoderma. This diagnosis is very important for prognosis and therapeutic management of the disease.

Chemical Leukoderma Associated with Methylphenidate Transdermal System: Data From the US Food and Drug Administration Adverse Event Reporting System

OBJECTIVE

To identify and characterize cases of chemical leukoderma, an underrecognized adverse event, associated with the methylphenidate transdermal system (MTS) reported to the US Food and Drug Administration Adverse Event Reporting System (FAERS).

STUDY DESIGN

We searched the Food and Drug Administration Adverse Event Reporting System for reports of chemical leukoderma associated with MTS, received by the Food and Drug Administration from April 6, 2006 to December 23, 2014.

RESULTS

We identified 51 cases of chemical leukoderma reported with the use of MTS. The median age was 11 years; 43 cases reported leukoderma at or near the application site only, and 7 reported leukoderma at other parts of the body in addition to the application site; 1 case did not provide enough information to confirm the affected site. The time to onset ranged from 2 months to 4 years after the initiation of MTS. MTS was discontinued in 31 cases. Thirteen patients were prescribed treatment for repigmentation. Three cases reported continued spread of leukoderma after MTS was discontinued. Nineteen cases were diagnosed as vitiligo, including 5 cases reporting histologic features consistent with vitiligo. Leukoderma was persistent in all cases. The median follow-up interval after the discontinuation of MTS in 23 cases was 14 months.

CONCLUSIONS

As outlined in recent changes to the prescribing information for MTS, health care professionals need to be aware of the potential risk of chemical leukoderma caused by MTS, especially given that chemical leukoderma is often misdiagnosed as idiopathic vitiligo. MTS should be discontinued at the earliest sign of pigment loss and other treatment options considered.

Clinical and epidemiological analysis in 149 cases of rhododendrol-induced leukoderma

Rhododendrol-induced leukoderma is an acquired depigmentation that develops mainly at the contact site after repeated use of skin-whitening cosmetics containing rhododendrol. In most cases, cessation of further depigmentation or occurrence of repigmentation is observed after discontinuing the use of cosmetics. However, some patients develop vitiligo vulgaris through the spread of depigmentation into the non-exposed areas. Our study aims to investigate the patient-specific factors that may affect the extent of depigmentation or repigmentation, as well as development of vitiligo vulgaris. The degree of depigmentation of the face, neck and hands where exposed to rhododendrol was scored using photographs over time. The relationships between depigmentation score at first visit/improvement rate of depigmentation score and patient demographics were evaluated and three important clinical observations were made. First, repigmentation of the face was superior compared with that of the hands and neck, suggesting a possible role for the migration and differentiation of melanocyte stem cells from hair follicles, as a mechanism of repigmentation. Second, the intensity of rhododendrol exposure did not contribute to differences in the severity of depigmentation. This suggested a possibility of underlying genetic susceptibility to melanocyte cytotoxicity or immune reaction. Third, depigmentation score at first visit and past history of atopic dermatitis were significantly high in patients who developed vitiligo vulgaris. This suggested that severe chemical damage of melanocytes by rhododendrol leads to a higher risk of developing vitiligo vulgaris through the possible involvement of an immune reaction. These clinical observations may help to further understand the pathogenesis of rhododendrol-induced leukoderma.

Cellular stress and innate inflammation in organ-specific autoimmunity: lessons learned from vitiligo

For decades, research in autoimmunity has focused primarily on immune contributions to disease. Yet recent studies report elevated levels of reactive oxygen species and abnormal activation of the unfolded protein response in cells targeted by autoimmunity, implicating cellular stress originating from the target tissue as a contributing factor. A better understanding of this contribution may help to answer important lingering questions in organ-specific autoimmunity, as to what factors initiate disease and what directs its tissue specificity. Vitiligo, an autoimmune disease of the skin, has been the focus of translational research for over 30 years, and both melanocyte stress and immune mechanisms have been thought to be mutually exclusive explanations for pathogenesis. Chemical-induced vitiligo is a unique clinical presentation that reflects the importance of environmental influences on autoimmunity, provides insight into a new paradigm linking cell stress to the immune response, and serves as a template for other autoimmune diseases. In this review, I will discuss the evidence for cell stress contributions to a number of autoimmune diseases, the questions that remain, and how vitiligo, an underappreciated example of organ-specific autoimmunity, helps to answer them.

Hair dye dermatitis and p-phenylenediamine contact sensitivity: A preliminary report

BACKGROUND

The contact allergic reactions from p-phenylenediamine (PPD) in hair dyes vary from mild contact dermatitis to severe life- threatening events (angioedema, bronchospasm, asthma, renal impairment).

OBJECTIVES

To study the clinical patterns and PPD contact sensitivity in patients with hair-dye dermatitis.

MATERIALS AND METHODS

Eighty (M:F 47:33) consecutive patients aged between 18 and 74 years suspected to have contact allergy from hair dye were studied by patch testing with Indian Standard Series including p-phenylenediamine (PPD, 1.0% pet).

RESULTS

54 Fifty-four (M:F 21:33) patients showed positive patch tests from PPD. Eight of these patients also showed positive patch test reaction from fragrance mix, thiuram mix, paraben mix, or colophony. Fifty-seven (71%) patients affected were aged older than 40 years. The duration of dermatitis varied from < 1 month to > 1 year with exacerbation following hair coloring. Forty-nine patients had dermatitis of scalp and/or scalp margins and 23 patients had face and neck dermatitis. Periorbital dermatitis, chronic actinic dermatitis, and erythema multiforme-like lesions were seen in 4, 2, and 1 patients, respectively.

CONCLUSIONS

Hair dyes and PPD constitute a significant cause of contact dermatitis. There is an urgent need for creating consumer awareness regarding hair-dyes contact sensitivity and the significance of performing sensitivity testing prior to actual use.

Confetti-like depigmentation: A potential sign of rapidly progressing vitiligo

BACKGROUND

Confetti-like depigmentation was noted in patients reporting recent worsening of vitiligo.

OBJECTIVE

We sought to determine if confetti-like depigmentation is a marker of rapidly progressing vitiligo.

METHODS

Review of patient records and images of patients from a vitiligo registry resulted in 7 patients with 12 images that fit inclusion criteria and were evaluated for percent depigmentation by 3 independent reviewers. The Vitiligo Disease Activity Score and the Koebner Phenomenon in Vitiligo Score in an additional cohort of patients with confetti-like lesions were compared with patients who had vitiligo without confetti-like lesions.

RESULTS

The mean percentage of depigmentation at baseline was 19.2%, which increased to 43.9% in images obtained at a mean of 16 weeks of follow-up. Vitiligo Disease Activity Score and Koebner Phenomenon in Vitiligo Score were significantly higher in the patients with confetti-like lesions compared with those without confetti-like lesions. A skin biopsy specimen of a confetti-like lesion in 1 patient revealed an inflammatory infiltrate in the papillary dermis with CD8(+) T cells localized to the dermoepidermal junction.

LIMITATIONS

Small, single-center retrospective review and lack of full-body photographs are limitations.

CONCLUSIONS

A confetti-like pattern of depigmentation may be a negative prognostic indicator for patients with rapidly progressing vitiligo. Further, prospective studies to evaluate this physical finding should be performed.

Dermatoses due to Indian cultural practices

A wide prevalence of socio-religious and cultural practices in the Asian subcontinent often leads to multitude of skin diseases which may be missed by the dermatologists because of a lack of awareness. ‘Henna’ use causes IgE-mediated hypersensitivity reactions and contact dermatitis. ‘Kumkum’ application can result in pigmented contact dermatitis and lichen planus pigmentosus. Sticker ‘bindis’ and ‘alta’ induce contact leukoderma. Irritant and allergic contact dermatitis occurs after playing with ‘Holi’ colors. Threading and drawstring dermatitis lead to koebnerization of pre-existing dermatoses, infections and even squamous cell carcinoma of skin. Mild irritant reactions and contact sensitization occur secondary to balm and hair oil use. ‘Mudichood’ represents the comedogenic effect of hair oils combined with occlusion and humidity. Aromatherapy oils can cause contact dermatitis and photosensitive reactions. Heavy metal and steroid toxicity along with severe cutaneous adverse effects like erythroderma can occur as a consequent to the use of alternative medicines. Squamous cell carcinoma due to chronic heat exposure from the heating device “kangri” is seen in Kashmiris. Prayer nodules in Muslims and traction alopecia in Sikhs illustrate how religious practices can negatively affect the skin. With increasing globalization and migration, the practice of indigenous customs and traditions is no longer limited to regional territories, making it imperative for the dermatologists to be acquainted with the cutaneous side effects they can cause.

A Multicenter Collaborative Study by the Korean Society of Vitiligo about Patients' Occupations and the Provoking Factors of Vitiligo

Background

It was previously thought that persons with genetic predispositions to vitiligo develop the condition after exposure to various precipitating environmental factors. However, in many cases, the aggravating factors of vitiligo have not been clearly identified.

Objective

To identify the aggravating factors of vitiligo in the working environment and daily life.

Methods

A total of 489 vitiligo patients were recruited from 10 institutions in South Korea; patients were provided with a questionnaire about environmental factors and behavior patterns in the workplace and in daily life, and their association with vitiligo.

Results

Ninety-five of the 470 enrolled patients (20.2%) answered that environmental risk factors in daily life and in the workplace affected the development of vitiligo. The most frequently attributed causes were trauma and burn (13.6%), followed by sunlight (12.8%), stress (12.8%), cleaning products/disinfectant/chemicals (4.9%), and hair dye (2.1%).

Conclusion

Vitiligo of the hand and foot was associated with frequent exposure to aggravating materials and overexposure to sunlight, along with frequent trauma of these areas, all of which could be considered important risk factors of vitiligo. The development of vitiligo could potentially be controlled through the early detection of aggravating factors.

Compensation for occupational skin diseases

The Korean list of occupational skin diseases was amended in July 2013. The past list was constructed according to the causative agent and the target organ, and the items of that list had not been reviewed for a long period. The revised list was reconstructed to include diseases classified by the International Classification of Diseases (10th version). Therefore, the items of compensable occupational skin diseases in the amended list in Korea comprise contact dermatitis; chemical burns; Stevens-Johnson syndrome; tar-related skin diseases; infectious skin diseases; skin injury-induced cellulitis; and skin conditions resulting from physical factors such as heat, cold, sun exposure, and ionized radiation. This list will be more practical and convenient for physicians and workers because it follows a disease-based approach. The revised list is in accordance with the International Labor Organization list and is refined according to Korean worker's compensation and the actual occurrence of occupational skin diseases. However, this revised list does not perfectly reflect the actual status of skin diseases because of the few cases of occupational skin diseases, incomplete statistics of skin diseases, and insufficient scientific evidence. Thus, the list of occupational diseases should be modified periodically on the basis of recent evidence and statistics.

Provoking factors, including chemicals, in Dutch patients with vitiligo

BACKGROUND

In vitiligo, many provoking factors have been described, but epidemiological data, especially on the role of contact with chemicals, are scarce.

OBJECTIVE

To obtain an insight into the patient-reported factors provoking vitiligo, including contact with chemicals.

METHODS

A retrospective cohort study was conducted on all 1264 patients with vitiligo who visited the Netherlands Institute for Pigment disorders from January 2003 to December 2007. Patients for whom an exogenous provoking factor was recorded were sent a questionnaire. Subsequently, patients who mentioned a chemical provoking factor were contacted to elucidate the alleged causal relationship between exposure to the chemical and the onset of vitiligo.

RESULTS

A total of 300 out of the 1264 patients indicated that provoking factors had played a role in their disease. Two hundred and forty-six patients were sent a questionnaire, which was returned by 177 (response rate of 72%). Emotional stress was indicated as a provoking factor in 98 patients (55.4%), 51 patients (28.8%) recorded sunburn, 34 patients (19.2%) recorded mechanical factors and 20 patients (11.3%) other factors. Of 29 patients (16.4%) who indicated a chemical factor, a presumed causal relationship could be corroborated in four. The chemicals involved were para-tertiary butylphenol (n = 2), captan (n = 1) and diphencyprone (n = 1).

CONCLUSION

The majority of the patients with vitiligo from this study did not mention provoking factors, but the ones who did point to emotional stress in more than half of the cases. Of the 29 patients who assigned chemical provoking factors, solvents were mainly indicated. However, a presumed relationship with the chemical could be corroborated in only four patients.

Innate immune mechanisms in vitiligo: danger from within

Vitiligo is an autoimmune disease of the skin in which melanocytes are destroyed by antigen-specific T cells, resulting in patchy depigmentation. Although adaptive immunity plays a clear role in disease progression, initiating factors are largely unknown. Many studies report that cellular stress pathways are dysregulated in melanocytes from vitiligo patients, suggesting that melanocyte-intrinsic defects participate in disease pathogenesis. Recent studies reveal that melanocyte stress generates damage-associated molecular patterns that activate innate immunity, thus connecting stress to organ-specific inflammation. Genetic studies in vitiligo support a role for stress, innate immunity, and adaptive mechanisms. Here, we discuss advances in the field that highlight how cellular stress, endogenous danger signals, and innate immune activation promote the onset of vitiligo.