Expert opinion about laser and intense pulsed light (IPL)-induced leukoderma or vitiligo: a cross-sectional survey study

Vitiligo patients may desire laser hair removal, skin rejuvenation, vascular treatments, and other laser or intense pulsed light (IPL) assisted treatments. However, there is a risk of inducing new depigmented patches (Koebner phenomenon). In absence of guidelines on the safe use of laser or IPL in vitiligo patients, dermatologists tend to be reluctant to administer these treatments. The aim of this survey study was to provide an estimation of the occurrence and related risk factors of laser/IPL-induced leukoderma or vitiligo. A cross-sectional survey study was performed among 15 vitiligo experts from 11 countries, with 14 questions about affected patients, involved laser/IPL treatments and the physicians' approach. In a total of 11,300 vitiligo patients, laser/IPL-induced leukoderma or vitiligo was reported in 30 patients (0.27%). Of these, 12 (40%) patients had a medical history of vitiligo and seven (58%) of these patients had stable (> 12 months) vitiligo before the treatment. Most frequently reported were hair removal procedures and localization of the face and legs. Side effects like blistering, crusting, and erosions occurred in 56.7% of the cases. These vitiligo experts based their advice on the risk of the laser treatment on stability of the vitiligo (43%) and activity signs (50%), and 50% discuss the risks before starting a laser treatment. Relevant activity signs are the Koebner phenomenon (57.1%), confetti-like lesions (57.1%) and hypochromic borders (50%). Laser-induced leukoderma or vitiligo is an uncommon phenomenon. Remarkably, a minority had a medical history of vitiligo of which 58% were stable. Consequently, most cases could not have been prevented by not treating vitiligo patients. However, a majority had laser/IPL-induced skin damage. Therefore, caution is advised with aggressive settings and test-spots prior to the treatment are recommended. This study showed significant variation in the current recommendations and approach of vitiligo experts regarding laser/IPL-induced leukoderma or vitiligo.

Recipient-to-Donor Ratios in the Surgical Treatment of Vitiligo, Leukoderma, and Piebaldism: A Retrospective Review

BACKGROUND

The autologous noncultured melanocyte keratinocyte transplant procedure (MKTP) has emerged as a popular grafting technique with proven efficacy for achieving repigmentation. However, there remains no consensus regarding the optimal recipient-to-donor (RD) ratio required to achieve acceptable repigmentation. In this retrospective cohort study of 120 patients, we sought to examine whether expansion ratios impact the repigmentation success rates following MKTP.

RESULTS

A total of 69 patients (mean [SD] age was 32.4 [14.3] years, mean follow-up was 30.4 [22.5] months, 63.8% were male; 55% were dark-skinned individuals [Fitzpatrick IV-VI]) were included. The mean percent change in the Vitiligo Area Scoring Index (VASI) was 80.2 (±23.7; RD of 7.3) in patients with focal/segmental vitiligo (SV), 58.3 (±33.0; RD of 8.2) in those with non-segmental vitiligo (NSV), and 51.8 (±33.6; RD of 3.7) in those with leukoderma and piebaldism. Focal/SV was positively associated with a higher percent change in VASI (parameter estimate: 22.6, p value <0.005). In the SV/focal group, non-white patients had a higher RD ratio compared to White individuals (8.2 ± 3.4 vs. 6.0 ± 3.1, respectively, p value = 0.035).

DISCUSSION

In our study, we found that patients with SV were significantly more likely to achieve higher repigmentation rates compared to those with NSV. Although repigmentation rates were higher in the low expansion ratio group than in the high expansion ratio group, we did not observe a significant difference between the two groups.

CONCLUSION

MKTP is an effective therapy for restoring repigmentation in patients with stable vitiligo. Therapeutic response of vitiligo to MKTP appears to be influenced by the type of vitiligo, rather than a specific RD ratio.

Copper chelation by d-penicillamine alleviates melanocyte death induced by rhododendrol without inhibiting tyrosinase

Oxidative metabolism of rhododendrol (RD), a skin-whitening ingredient, by tyrosinase has caused leukoderma in a certain population of Japanese consumers. Toxic RD metabolites and reactive oxygen species are proposed causes for the melanocyte death. However, the mechanism by which reactive oxygen species are produced during RD metabolism remains elusive. Some phenolic compounds are known to act as suicide substrates for tyrosinase, resulting in release of a copper atom and hydrogen peroxide during its inactivation. We hypothesized that RD may be a suicide substrate for tyrosinase and that the released copper atom may be responsible for the melanocyte death through hydroxyl radical production. In line with this hypothesis, human melanocytes incubated with RD showed an irreversible decrease in tyrosinase activity and underwent cell death. A copper chelator, d-penicillamine, markedly suppressed the RD-dependent cell death without significantly affecting the tyrosinase activity. Peroxide levels in RD-treated cells were not affected by d-penicillamine. Given the unique enzymatic properties of tyrosinase, we conclude that RD acted as a suicide substrate and resulted in release of a copper atom and hydrogen peroxide, which would collectively impair melanocyte viability. These observations further imply that copper chelation may alleviate chemical leukoderma caused by other compounds.

Upregulation of CD86 and IL-12 by rhododendrol in THP-1 cells cocultured with melanocytes through ROS and ATP

BACKGROUND

The tyrosinase inhibitor rhododendrol (RD), used as a skin whitening agent, reportedly has the potential to induce leukoderma.

OBJECTIVE

Although an immune response toward melanocytes was demonstrated to be involved in leukoderma, the molecular mechanism is not fully understood.

METHODS

We hypothesized that if RD is a pro-hapten and tyrosinase-oxidized RD metabolites are melanocyte-specific sensitizers, the sensitizing process could be reproduced by the human cell line activation test (h-CLAT) cocultured with melanocytes (h-CLATw/M) composed of human DC THP-1 cells and melanoma SK-MEL-37 cells. Cell surface expression, ROS generation and ATP release, mRNA expression, and the effects of several inhibitors were examined.

RESULTS

When RD was added to the h-CLATw/M, the expression of cell-surface CD86 and IL-12 mRNA was greatly enhanced in THP-1 cells compared with those in the h-CLAT. The rapid death of melanoma cells was induced, with ROS generation and ATP release subsequently being greatly enhanced, resulting in the cooperative upregulation of CD86 and IL-12. Consistent with those observations, an ROS inhibitor, ATP receptor P2X7 antagonist, or PERK inhibitor antagonized the upregulation. CD86 upregulation was similarly observed with another leukoderma-inducible tyrosinase inhibitor, raspberry ketone, but not with the leukoderma noninducible skin-whitening agents ascorbic acid and tranexamic acid.

CONCLUSION

RD is a pro-hapten sensitizer dependent on tyrosinase that induces ROS generation and ATP release from melanocytes for CD86 and IL-12 upregulation in DCs, possibly leading to the generation of tyrosinase-specific cytotoxic T lymphocytes. The coculture system h-CLATw/M may be useful for predicting the sensitizing potential to induce leukoderma.

Melanocytotoxic chemicals and their toxic mechanisms

Melanocyte cell death can lead to various melanocyte-related skin diseases including vitiligo and leukoderma. Melanocytotoxic chemicals are one of the most well-known causes of nongenetic melanocyte-related diseases, which induce melanocyte cell death through apoptosis. Various chemicals used in cosmetics, medicine, industry and food additives are known to induce melanocyte cell death, which poses a significant risk to the health of consumers and industrial workers. This review summarizes recently reported melanocytotoxic chemicals and their mechanisms of toxicity in an effort to provide insight into the development of safer chemicals.

Vitiligo-like leukoderma as an indicator of clinical response to immune checkpoint inhibitors in late-stage melanoma patients

PURPOSE

Although development of immune checkpoint inhibitors has revolutionized the treatment of metastatic melanoma, more than a half of treated patients experience disease progression during therapy. Cases of spontaneous vitiligo-like leukoderma have been described in melanoma patients and have been associated with a favorable outcome. This vitiligo-like leukoderma can also appear in melanoma patients undergoing immune therapies such as immune checkpoint inhibitors. However, no consensus exists about the relationship between vitiligo-like leukoderma onset and improved overall survival. Our study investigates the possible association between the onset of vitiligo-like leukoderma during immune checkpoint inhibitor treatment and a better prognosis.

METHODS

A non-concurrent cohort study was conducted by identifying retrospectively 280 patients who had inoperable or metastatic melanoma and had undergone immune therapy with checkpoint inhibitors in any line of treatment. Toxicities developed during therapy were evaluated.

RESULTS

Among the 280 study participants, 50% developed at least one type of toxicity, and vitiligo-like leukoderma was observed in 43 patients (15.4%). In the multivariate Cox model, a protective effect for mortality was observed for patients with vitiligo-like leukoderma development (HR : 0.23; 95% CI 0.11-0.44, p < 0.0001). In a sub-group analysis comprising only cutaneous melanoma in first line of treatment (N = 153), occurrence of vitiligo-like leukoderma was also an independent predictor factor for duration of clinical benefits measured by time to the next treatment (HR: 0.17; 95% CI 0.06-0.44).

CONCLUSION

Our findings indicate that onset of vitiligo-like leukoderma during melanoma treatment could be a marker of favorable outcome in patients treated with immune checkpoint inhibitors.

Thymol-Induced Chemical Leukoderma Successfully Treated with 308-Nanometer Excimer Laser

Introduction

Chemical leukoderma (CL) is an acquired depigmenting disorder caused by repeated exposure to chemical compounds. Thymol is a phenol derivative used as a preservative or antiseptic in many commercially available products. Here, we present the second reported case of CL caused by a thymol-containing compound.

Case Presentation

A 48-year-old woman presented with a 4-month history of depigmentation of the nail folds of all ten fingers. This occurred after 1 month of twice-daily application of a thymol-containing compound intended for the removal of gel nails. No improvement was noted after the product was discontinued. There was no family history of vitiligo or other autoimmune disorders. On physical exam, depigmentation of all ten proximal and lateral nail folds was seen, with accentuation on Wood's lamp exam. Partial re-pigmentation was achieved after 32 treatments with 308-nm excimer laser.

Discussion

A thorough history and physical exam are instrumental in differentiating CL from other causes of depigmentation. Avoidance of the offending agent is an essential part of management. It is important to note that many cosmetic products are not tightly regulated by the FDA. Excimer laser is an effective treatment for CL with a favorable side-effect profile.

Is vitiligo associated with wearing plastic shoes in a podoconiosis endemic region of Ethiopia?

INTRODUCTION

Endemic non-filarial elephantiasis also known as podoconiosis often affects bare footed farmers and is endemic in Ethiopia. The disease is prevented by wearing shoes. We recently observed several patients presenting to a dermatology clinic with skin depigmentation after wearing plastic shoes ("shoe-contact vitiligo") which may deter shoe-wearing. We report on their sociodemographic and clinical characteristics.

METHODOLOGY

This is a retrospective study of 17 months at tertiary level Hospital in Ethiopia. Patient data was retrieved from medical record department. We compared sociodemographic and clinical characteristics of patients presenting with idiopathic and shoe-contact vitiligo. Data was presented descriptively.

RESULTS

Of 460 vitiligo cases, 190 (41%) were shoe-contact vitiligo and the rest, idiopathic. The former was more common in females (Odds Ratio, OR = 2.5, P < 0.001) and those in rural areas (OR = 4.8, P < 0.001). Fifty-five percent with shoe-contact vitiligo had itching and/or burning sensation, compared to just 2% with idiopathic vitiligo (P < 0.001) and some had ulcerations (8%). Idiopathic vitiligo had no such findings. Skin discoloration occurred within three weeks (on average) after wearing plastic shoes, 91% of lesions were symmetrical and involved areas of the feet covered with plastic shoes. Symmetric lesions were observed in only 11% of idiopathic vitiligo (OR = 81, P < 0.001).

CONCLUSIONS

Shoe-contact vitiligo was significantly associated with wearing cheap plastic shoes. The exact chemical culprit(s) needs to be identified. This will allow introducing quality control regulations and rigorous monitoring of shoe production sites.

Autoimmune diseases affecting skin melanocytes in dogs, cats and horses: vitiligo and the uveodermatological syndrome: a comprehensive review

Autoimmune dermatoses targeting melanocytes have gained attention in human medicine due to their progressive nature and the social impact suffered by affected individuals. In veterinary medicine, vitiligo and the uveodermatological syndrome are the two autoimmune diseases that are known to affect skin melanocytes.In the first part of this article, we will review the signalment, clinical signs, histopathology and the treatment outcome of vitiligo in dogs, cats and horses; where pertinent, we compare the animal diseases to their human homologue. In a similar fashion, the information on the uveodermatological syndrome in dogs is reviewed and, where relevant, it is compared to the Vogt-Koyanagi-Harada (VKH) syndrome in humans.Canine, feline and equine vitiligo have many features that mirror their human counterparts. The most effective treatment and outcome of vitiligo in animals remain unclear. The canine uveodermatological syndrome resembles the incomplete VKH variant in humans; for affected individuals, an immediate diagnosis and aggressive treatment are crucial to prevent the development of blindness.

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.

Treatment of Laser Therapy-Induced Punctate Leukoderma Using a 308-nm Excimer Laser

Punctate leukoderma presents as numerous, distinct, round or oval depigmented spots. Recently, laser therapy-induced punctate leukoderma associated with various Q-switched laser and carbon dioxide laser have been reported. A 25-year-old man presented with numerous, discrete, round, confetti-like, depigmented macules on his left neck. He had undergone 3 sessions of 532-nm Q-switched Neodymium: Yttrium-Aluminum-Garnet laser treatment for café-au-lait macules three years ago. After the last laser treatment session, the punctate leukoderma had been developed. We started treatment with the 308-nm excimer laser twice a week. After 7 months of treatment duration, complete repigmentation was achieved without serious adverse effects. We recommend the 308-nm excimer laser as an effective treatment modality for laser therapy-induced punctate leukoderma.

Cutaneous manifestations associated with melanoma

Melanoma is a malignancy most commonly arising from the skin; therefore, primary melanoma characteristics are usually the first cutaneous manifestations of melanoma. Cutaneous metastases, which can occur locally or diffusely, are important to detect in a timely manner as treatments for advanced melanoma that impact survival are now available. Melanoma can be associated with local or diffuse pigmentation changes, including depigmentation associated with the leukodermas and hyperpigmentation associated with diffuse melanosis cutis. The leukodermas occur frequently, illustrate the immunogenic nature of melanoma, and may impact prognosis. Paraneoplastic syndromes in association with melanoma are rare, though can occur.

Biochemical, cytological, and immunological mechanisms of rhododendrol-induced leukoderma

Recently, an unexpected outbreak of patients with leukoderma occurred in Japan with the use of brightening/lightening cosmetics containing rhododendrol (RD). Patients developed leukoderma mostly on the skin sites repeatedly applied with RD, but some patients also had vitiligo-like lesions on the non-applied sites. RD is a tyrosinase-competitive inhibiting substance, thereby serving as an inhibitor of melanin synthesis. Upon inhibition of tyrosinase, RD is converted to new products such as tyrosinase-catalyzed hydroxyl-metabolite, which damage melanocytes. The melanocyte cell lysates seem to induce T-cell response. The frequencies of CD8+ T cells in both lesional skin and peripheral blood are significantly higher in the RD leukoderma as well as non-segmental vitiligo patients than in normal controls. In HLA-A*02:01 positive cases, circulating Melan-A-specific cytotoxic T cells can be detected at a high frequency. It is thus suggested that RD-induced leukoderma is induced by not only cytolysis of melanocytes but also subsequent immune reactions toward melanocytes.

Immunological basis of melanoma-associated vitiligo-like depigmentation

Vitiligo is a skin condition characterized by white, hypopigmented macules. Melanocyte loss is a feature of the disease, and it has been hypothesized that an autoimmune mechanism could be responsible for the depigmentation. Melanoma is a malignancy that develops in melanocytes; if not detected and treated early, it is often deadly. Leukoderma, a condition characterized by depigmentation of the skin, is sometimes associated with malignant melanoma. An immune response against melanocyte antigens leading to destruction of either melanoma cells or melanocytes has been observed in both vitiligo and melanoma. Studies in animal models and humans have shown that humoral and cell-mediated immune responses are involved in modulating cytotoxic activity against tumor cells and normal melanocytes. The study of factors associated with anti-tumor immunopathogenic mechanisms -autoimmunity for example- may provide us with tools for the diagnosis and treatment of diseases such as vitiligo and malignant melanoma.