On the pathogenesis of idiopathic guttate hypomelanosis

Evaluation of diagnostic accuracy of dermoscopy in some common hypopigmented skin diseases

BACKGROUND

Diagnosis of cutaneous hypopigmentation can sometimes be challenging. Dermoscopy may play a role in identifying hypo or-depigmented dermatoses. The aim was to investigate which dermoscopic criteria represent potent indicators for the diagnosis of vitiligo, nevus depigmentosus, pityriasis alba, hypopigmented pityriasis versicolor, idiopathic guttate hypomelanosis, hypopigmented mycosis fungoides (MF), lichen sclerosus et atrophicus and ash leaf hypopigmented macules of tuberous sclerosis, and evaluate their diagnostic accuracy. 168 individuals diagnosed with one of these hypopigmented disorders were evaluated for the presence or absence of predetermined dermoscopic criteria. Evaluation of dermatoscopic characteristics in each condition and analysis for sensitivity and specificity of dermatoscopic diagnosis in these hypopigmented lesions was performed. The starburst pattern, micro-koebnerization, and trichrome pattern were unique to vitiligo diagnosis. Vitiligo had higher comet-tail appearance, perifollicular pigmentation, and perilesional hyperpigmentation than other hypopigmented illnesses. Other hypopigmented lesions had greater incidence of amoeboid pattern, faint or diminished pigment network, islands of pigmentation, ill-defined boundaries, pseudopods, and widespread scaling than vitiligo. Finally, perifollicular scaling, comedo-like openings, blue-gray specks, and fibrotic regions excluded vitiligo. Dermoscopy can help identify common hypopigmented skin lesions and reduce the need for skin biopsy. Nevus depigmentosus, pityriasis alba and idiopathic guttate hypomelanosis were the top three hypopigmented dermatoses that could be diagnosed by dermoscopy with 100% sensitivity. Vitiligo was in the second rank (94.7%), followed by lichen sclerosis et atrophicus (93.3%) then hypopigmented MF at 81.2% sensitivity. Dermoscopy sensitivity was lowest in pityriasis versicolor and ash leaf macules of tuberous sclerosis (52.6% and 46.7%, respectively).

Idiopathic guttate hypomelanosis: Presentation and Management

Idiopathic guttate hypomelanosis (IGH) is a benign, typically asymptomatic, acquired leukoderma characteristically affecting mature individuals. Although the etiopathogenesis is unclear, chronic sun exposure and senile degeneration are important triggers. Researchers have been engaged in a continuous effort to unveil the gray areas encompassing different aspects of IGH pathogenesis. IGH is a clinical diagnosis; however, histopathology and dermoscopy may aid in quetionable cases. Patients often seek cosmetic treatment. There has been no standard therapy for this condition. Newer treatment modalities range from topical agents to procedure-based therapies and have enhanced the therapeutic armamentarium. Here we discuss the pathogenesis, presentation, and management of IGH.

Do oxidative stress and melanin accumulation contribute to the pathogenesis of idiopathic guttate hypomelanosis: A prospective case-control study

BACKGROUND

Oxidative stress parameters have been reported to be significantly higher than controls in diverse disorders of pigmentation but no such data seem to be extant for IGH.

OBJECTIVES

To verify whether heightened oxidative stress levels are seen in patients with IGH (compared with matched controls) and quantify the same in blood using appropriate biochemical markers. Further, an attempt to determine if there might be any correlation between the amount of oxidative stress and the severity of the disease.

METHODOLOGY

This prospective case-control study was conducted in Northern India. Thirty Indian patients (Fitzpatrick skin phototype (SPT) IV-V) were included. The diagnosis of IGH lesions was confirmed based on characteristic clinical, and dermoscopic characteristics and confirmed on histopathological examination (H & E) of one of the lesions.

RESULTS

The oxidative stress enzyme level was significantly higher among the cases compared to controls which were statistically significant (p < 0.05). A positive correlation was also observed between the levels of these markers and number of lesions, but this finding was statistically not significant [p > 0.05]. Assessment of melanin level by Dopa staining method in the IGH lesions revealed irregularly distributed melanin with areas of high and low melanin content and greater accumulation in the basement layer.

CONCLUSION

The results of this probably the first study evaluating oxidative stress in IGH show that the oxidative stress is increased in patients with IGH. Level of oxidative stress seems to be correlated with both age of the patient (more in the elderly) and number of lesions.

[Treatment of pigmentation disorders in association with systemic diseases]

Pigmentation disorders are a frequent skin problem and incorporate a broad spectrum of diseases, caused by an abnormal melanin pigmentation or also non-melanin pigmentation of the skin. Both hypermelanosis and hypomelanosis can be hereditary or acquired. This article summarizes the treatment approaches that are used in the majority of acquired pigmentation disorders of the skin. The following forms of hypermelanosis are addressed: lentiginosis, hyperpigmentation due to endocrine disorders or other systemic diseases, drug-induced hyperpigmentation. Acquired hypomelanoses include postinflammatory hypomelanosis, chemical depigmentation, idiopathic guttate hypomelanosis and punctate leucoderma. With reference to non-melanin pigmentation, the exogenous pigmentation due to chemicals, metals and drug exposure are discussed. The treatment is primarily based on finding the cause of the alterations to the pigment. The affected area, age and ethnic origin are also important factors. The spectrum of therapeutic options is broad: topical agents, chemical peeling, systemic agents, laser and light-based treatment. As some of these treatment procedures can have side effects, the availability of a protocol that contains information on the drug concentration, dose, parameters for laser treatment and the number of sessions is important. For every disorder the specific dermatological treatment is presented even when some pigmentation alterations that occur in association with systemic diseases, are cured by the treatment of the primary disease. Most diseases are exacerbated by exposure to UV light. Therefore, sun protection is recommended and a cosmetic coverage is indicated.

The color of skin: white diseases of the skin, nails, and mucosa

White diseases are a heterogenous group characterized by hypopigmentation or depigmentation. Skin and eye color are determined by the number and size of melanosomes present. Melanin is produced by melanosomes in the melanocytes present within the epidermis of the skin, uvea, and retinal pigmented epithelium (RPE). Conditions altering the number of melanocytes or concentration of melanin result in a lack of pigmentation, appearing as "white diseases" ranging from the well-known albinism and vitiligo to more esoteric white hand syndrome and Degos disease.

Pigmentation Disorders in the Elderly

Aging skin is subject to morphological change due to both intrinsic (skin tone, genetics, endogenous hormones) and extrinsic (chronic sun exposure, medications, exogenous pigments) factors. The broad spectrum of transformation includes both hypo- and hyperpigmentation. Although cutaneous pigmentary disorders are common in younger individuals, certain disorders are more prevalent in the geriatric population. This article reviews the epidemiology, pathophysiology, clinical appearance, treatment, and prognosis of pigmentary lesions that are predominant in the elderly.

Melanocyte abnormalities and senescence in the pathogenesis of idiopathic guttate hypomelanosis

BACKGROUND

Idiopathic guttate hypomelanosis (IGH) is a pigmentary disorder of unknown pathogenesis characterized by small discrete white macules. In the skin, epidermal melanin unit between melanocytes and keratinocytes is responsible for melanin synthesis and equal distribution of melanin pigment.

OBJECTIVE

Therefore, this study was designed to check the role of melanocytes in the pathogenesis of IGH.

METHODS

For this study, six IGH patients and six controls were enrolled. Melanin content was checked in the skin sections and in the cultured melanocytes. Senescence was checked in the lesional skin of IGH patients by comparing the mRNA and protein expression of senescence markers p16, hp1, and p21.

RESULTS

Cultured melanocytes from the IGH patients showed morphological changes in comparison to the control melanocytes. Melanocytes from IGH patients were bigger in size with very small and retracted dendrites as compared to the control melanocytes. Melanin accumulation was more in the IGH patients as compared to the controls. Our results showed that expression of p16, p21, and hp1 was significantly higher in lesional skin of IGH patient as compared to healthy controls.

CONCLUSION

This study revealed large-sized melanocytes with small and retracted dendrites in IGH patients. Accumulation of more melanin in the IGH melanocytes might be due to problem in the transfer of melanin from melanocytes to keratinocytes. Accumulation of melanin can lead to the senescence in the melanocytes of IGH patients.

Idiopathic Guttate Hypomelanosis: A Review of its Etiology, Pathogenesis, Findings, and Treatments

Idiopathic guttate hypomelanosis is a common acquired leukoderma characterized by multiple, discrete round or oval, porcelain-white macules on sun-exposed areas, especially on the extensor surface of forearms and pretibial areas. It usually affects individuals aged over 40 years and the likelihood of acquiring it increases with age. The exact pathogenesis remains controversial. However, there are several factors that are believed to be involved such as aging, ultraviolet exposure, trauma, genetic factors, autoimmunity, and local inhibition of melanogenesis. Despite the benign course of progression, many patients visit medical centers owing to cosmetic concerns and to confirm the natural course of idiopathic guttate hypomelanosis. Because there is no standard therapy for this condition, numerous medical and surgical treatments including intralesional corticosteroids, topical retinoids, topical calcineurin inhibitors, phenol peeling, cryotherapy, superficial dermabrasion, skin grafting, and ablative and non-ablative lasers have been tested with mixed results. This article will thoroughly review the etiology, pathogenesis, clinical presentations, histologic, dermoscopic, and ultrastructural findings, and the treatment of idiopathic guttate hypomelanosis.

Skip areas of retained melanin: a clue to the histopathological diagnosis of idiopathic guttate hypomelanosis

Biopsy findings in 55 cases of idiopathic guttate hypomelanosis (IGH) are reported. Most cases had a flat epidermis with loss of the rete pattern and a thickened orthokeratotic basket weave stratum corneum. The epidermis had markedly decreased to absent melanin in the basal layer and reduced numbers of melanocytes at the dermoepidermal junction. One-third of patients had a sparse perivascular lymphocytic infiltrate, whereas the rest had no significant dermal inflammation. These findings are in concordance with current literature. However, small foci of retained melanin in the basal layer (skip areas) alternating with larger areas of melanin loss were present in almost 80% of cases. This finding has not been reported earlier and appears to be quite specific to IGH and may be used as a clue to differentiate IGH from other similar conditions such as vitiligo and guttate morphea.

Therapeutic wounding - 88% phenol in idiopathic guttate hypomelanosis

Context:

Therapeutic wounding includes wounding the skin to induce pigmentation of the depigmented skin patches that was earlier used for repigmenting small patches of stable vitiligo. In this study, we have used the same principle to induce pigmentation in idiopathic guttate hypomelanosis (IGH) by spot peel with 88% phenol.

Aims:

To study the efficacy of phenol in causing repigmentation in IGH and its adverse effect profile.

Settings and Design:

Open prospective study.

Materials and Methods:

Twenty patients with 139 IGH macules were subjected to spot peel. Eighty-eight percent phenol was applied with an ear bud once a month for two sittings. Patients were assessed both subjectively and objectively after every session and at the end of 3 months of initiation of therapy.

Results:

Repigmentation was noted in 64% of IGH macules. More than 75% improvement was seen in 45% of the total IGH macules, while 41.5% showed 50-75% improvement at the end of three months. Persistent scabbing was the common adverse effect noted in 17.26% of lesions.

Conclusion:

Spot peel with 88% phenol is a safe, simple, cost-effective, outpatient procedure for IGH, which can be combined with other medical therapies.

The effect of fractional carbon dioxide lasers on idiopathic guttate hypomelanosis: a preliminary study

BACKGROUND

Idiopathic guttate hypomelanosis (IGH) is a commonly acquired leucoderma that is characterized by discrete, round or oval porcelain-white macules ∼2-5 mm in diameter that increases in number with age. A variety of therapies with variable success rates, including cryotherapy, superficial abrasion and topical retinoids are currently being used.

OBJECTIVES

The effects of fractional CO(2) laser therapy on IGH were investigated in this pilot study.

PATIENTS AND METHODS

A total of 40 patients with IGH were enrolled. The hypopigmented lesions were treated using a 10 600-nm carbon dioxide fractional laser (CO(2) FL). Two months after a single treatment, physicians' clinical assessments were performed and the patients' overall satisfaction was evaluated.

RESULTS

The mean age of enrolled patients was 57.5 ± 10.9 years and the gender ratio was 7 : 33. The face was the most commonly treated area, although the extremities are epidemiologically the most frequently affected areas. Two months after treatment, objective assessments performed by two independent dermatologists indicated more than 50% improvement in 36 patients (90%), compared with baseline. In addition, 33 patients (82.5%) were very satisfied or satisfied with just one session of CO(2) FL treatment. Although a few patients complained of long-standing erythema and postinflammatory hyperpigmentation, these problems spontaneously resolved within 2 months after the assessments. No other noticeable side effects were observed.

CONCLUSION

CO(2) FL might be a very convenient and effective modality for treating IGH without significant side effects.

Topical tacrolimus significantly promotes repigmentation in idiopathic guttate hypomelanosis: a double-blind, randomized, placebo-controlled study

BACKGROUND

Idiopathic guttate hypomelanosis (IGH) is an idiopathic disorder affecting a large number of people. Effective treatments are not yet available. Objectives To investigate the efficacy of topical 0.1% tacrolimus ointment compared with placebo in the treatment of IGH.

MATERIALS AND METHODS

Twenty-six patients were included in the study. Lesions on one side of the body were selected to have a treatment with 0.1% tacrolimus ointment, whereas those on the other side served as a control with placebo ointment that had the same physical appearance. Colorimeter was used to assess skin colour at baseline and at 1, 2, 3, 4 and 6 months of treatment.

RESULTS

Mean luminosity scale after adjusted for baseline from the treated side gradually decreased and reached statistical significance compared with the control group after 6 months of treatment (P = 0.019). Physicians' improvement grading score showed that 11% of the patients demonstrated improvement of their skin lesions on the treated side after 6 months' treatment.

CONCLUSION

Topical 0.1% tacrolimus ointment appeared to be an effective and safe treatment for IGH. The improvements were best observed by colorimetry, yet, they were not statistically significant upon clinical assessments.

Idiopathic guttate hypomelanosis-like lesions in patients with mycosis fungoides: a new adverse effect of phototherapy

BACKGROUND

Idiopathic guttate hypomelanosis (IGH) is a common pigmentary disorder, the aetiology and pathogenesis of which are largely unknown. The appearance of IGH-like lesions during phototherapy has been reported previously in only one patient.

OBJECTIVE

To describe the clinical and histological features of phototherapy-induced IGH-like lesions, their relation to ultraviolet dosimetry and the course of this eruption in patients with mycosis fungoides (MF).

METHODS

The files of all patients with MF who underwent phototherapy in our centre from 1992 to 2008 were searched to identify those in whom IGH-like lesions appeared during treatment. Results Among 87 patients with early-stage MF who underwent phototherapy, seven acquired IGH-like lesions during monotherapy with narrow-band ultraviolet B (NB-UVB; four patients) or psoralen and ultraviolet A (PUVA; three patients). All but one had a light complexion. The lesions appeared in areas exposed to ultraviolet light, and not exclusively on the skin previously involved by the disease. The mean number of exposures until appearance of the lesions was 92 for NB-UVB and 137 for PUVA. Biopsy study showed a decreased number of melanocytes. Phototherapy was discontinued in four patients, of whom three showed a partial or complete disappearance of the IGH-lesions. The other three patients are still receiving phototherapy, with no change in their IGH-like lesions.

CONCLUSIONS

Phototherapy may induce an eruption bearing similar clinical and histopathological features to IGH. The eruption is rare, appears to emerge only after prolonged therapy and seems to be reversible upon discontinuation of phototherapy. IGH-like eruption should be added to the list of side-effects of phototherapy.

Pigmentary Disorders in Latin America

Pigmentary disorders with hypopigmentation/depigmentation or hyperpigmentation may have special manifestations in Latin America. Most pigmentary disorders are commonly observed in all areas of Latin America, but a few are particularly seen in tropical and subtropical regions. In most pigmentary disorder ailments described, multiple factors involved in their pathogenesis are known, but etiology remains elusive. Some pigmentary disorders have peculiar clinical expressions and, in spite of being restricted to certain geographical areas, they may be observed in other world areas because of frequent traveling of affected patients. Therapy of most of these ailments is difficult or remains unknown.

Idiopathic guttate hypomelanosis: idiopathic or ultraviolet induced?

Idiopathic guttate hypomelanosis (IGH) is a common but often unrecognized skin disease with obscure etiopathogenesis. As the lesions mostly develop on the exposed parts of the extremities, ultraviolet has been hypothesized to induce these lesions. However, previous statistical studies did not confirm any association between ultraviolet and IGH. We describe a 72-year-old woman with mycosis fungoides in whom widespread IGH occurred during narrow band ultraviolet B (UVB) therapy. The lesion development in the trunk following narrow band UVB therapy suggests that these lesions may not be idiopathic and they may be associated with UV exposure although controversy exist in the literature. This case is particular as it reveals strong evidence on this relationship.

Confetti-like lesions with hyperkeratosis: a novel ultraviolet-induced hypomelanotic disorder?

Confetti leucoderma can occur in a variety of unrelated skin disorders and is often a diagnostic challenge. We describe a 33-year-old man with a history of mycosis fungoides and vitiligo. He developed disseminated 1-2-mm round-shaped leucodermic lesions 6 months after psoralen photochemotherapy and 12 months after systemic therapy with interferon. The skin lesions had a discrete hyperkeratotic scale. Multiple skin biopsies and immunohistochemical studies showed lamellar orthohyperkeratosis, papillomatosis, hypomelanotic keratinocytes but a normal number of melanocytes. Langerhans cells, in contrast, were reduced in lesional skin. Electron microscopy disclosed only a few type I and II melanosomes in lesional melanocytes, while keratinocytes were largely devoid of any melanosomes. This constellation of clinical, immunohistochemical and ultrastructural findings has not been reported before and distinguishes our case from leucoderma punctatum, idiopathic guttate hypomelanosis and disseminated hypopigmented keratoses. We suggest that the skin lesions observed in our patient represent an unusual response to ultraviolet damage to melanocytes followed by reactive epidermal hyperkeratosis.

Hypermelanocytic guttate and macular segmental hypomelanosis

We report two sisters, 27 and 30 years of age, with a cutaneous pigmentary anomaly, which seems to be a new entity. At the age of 26 years the elder sister developed an asymptomatic and persistent rash consisting of discrete, grouped, round to oval, guttate and nummular, hypopigmented macules, 0.2-5 cm in diameter. The distribution of the lesions was unilateral. They were located on the right side of the thorax with a moderately sharp demarcation in the mid-line and ran in a segmental distribution over the right arm, hand and fingers. Microscopic examination of lesional skin scrapings was negative for fungi. Examination with Wood's light accentuated the lesions from the surrounding normal skin. The younger sister had experienced identical, mostly guttate, skin lesions for many years, which at examination were distributed on all extremities and buttocks, and to a lesser degree on the trunk, but here in a segmental distribution. Histological examination (Masson-Fontana staining) of lesional skin of both sisters was identical. A slightly thinned epidermis and a marked decrease in pigmentation of the epidermal basal layer was seen. Electron microscopic examination of lesional skin showed an overall linear increase of morphologically and cytologically normal melanocytes just above the epidermal basal membrane. At many places the density of melanocytes was so high that the keratinocytes were displaced from the basal layer. The melanocytic dendrites extended into the suprabasal layer. The keratinocytes of lesional skin showed a decreased number of melanosomes. It is paradoxical that a hypomelanotic macule shows a histological picture of an increase in normal functioning melanocytes. In all probability a deficient melanosome transfer is responsible for this unexpected phenomenon.

Pigmentary disorders in ethnic skin

Pigmentary disorders are commonly seen in ethnic skin. They are psychologically problematic in darker skin. Treatment of many of these disorders remains difficult.

HLA-DQ3 is associated with idiopathic guttate hypomelanosis, whereas HLA-DR8 is not, in a group of renal transplant patients

BACKGROUND

The etiology of idiopathic guttate hypomelanosis (IGH) remains uncertain; however, solar exposure and heredity have been proposed as causative factors.

OBJECTIVE

To explore the genetic predisposition to the development of IGH.

METHODS

A comparative case-control study was performed at a dermatology department at a university hospital. Forty-seven subjects (22 renal transplant patients and 25 controls) were enrolled. Clinical examination and human leukocyte antigen (HLA) determination were performed.

RESULTS

In the group of subjects with HLA-DQ3 (10/13, P = 0.025), there was a statistically significant (P < 0.05) positive association for the presence of IGH; in the group of subjects with HLA-DR8 (6/6, P = 0.023), there was a statistically significant negative association for the presence of IGH.

CONCLUSIONS

The presence of HLA-DQ3 in patients with IGH suggests a genetic basis in a group of renal transplant subjects. HLA-DR8 was found in patients without IGH, and it could play a role as a "protective factor" preventing subjects from developing IGH.

Numbers and differentiation status of melanocytes in idiopathic guttate hypomelanosis

The etiology and pathogenesis of idiopathic guttate hypomelanosis (IGH) are largely unknown. To investigate whether the pathologic alteration in IGH involves changes in melanocytic differentiation, cell number, or both, we studied nine lesions of IGH by immunoperoxidase, using monoclonal antibodies against the KIT receptor and a panel of melanocyte differentiation antigens (tyrosinase-related protein-1, tyrosinase, and gp100/pme117). In each case, compared with grossly normal non-lesional skin, IGH lesions showed markedly reduced numbers both of KIT+ cells and of cells expressing melanocyte differentiation antigens (p < 0.0001). Double immunofluorescence labeling of lesions revealed only scattered cells with a less-differentiated phenotype, i.e. cells positive for KIT but having low or undetectable TRP-1. These results indicate that the pathogenesis of IGH involves an absolute decrease in the number of melanocytes; a block in melanocyte differentiation does not appear to be a major component of the process.

Prevalence of hypopigmented macules in a healthy population

OBJECTIVE

Although hypopigmented macules are an important manifestation of tuberous sclerosis (TS), the probability of TS in healthy individuals who have hypopigmented macules is unknown. The purpose of this study was to establish the prevalence of hypopigmented macules among a cross section of the general white population.

STUDY DESIGN

The skin of 423 white individuals younger than 45 years of age was screened for hypopigmented macules with ambient incandescent and fluorescent light and a Wood lamp. Indirect ophthalmoscopy was performed in patients with unexplained hypopigmentation to screen for retinal manifestations of TS.

RESULTS

Twenty individuals (4.7%) had at least one hypopigmented macule. Of these, four had more than one macule. None had more than three. Two (8%) of the 25 hypopigmented macules were identified only with a Wood lamp. Indirect ophthalmoscopy was performed in 13 (65%) of these 20 individuals. None showed the retinal findings of TS.

CONCLUSIONS

The prevalence of hypopigmented macules in the general population has been underestimated. The presence of a few hypopigmented macules on the skin of an otherwise healthy individual without a family history of TS need not prompt an evaluation to rule out this disorder.

Treatment of idiopathic guttate hypomelanosis with liquid nitrogen: light and electron microscopic studies

Idiopathic guttate hypomelanosis is a common skin disorder of unknown cause. Our studies have shown that significantly fewer dopa-positive melanocytes are in the white macules of idiopathic guttate hypomelanosis than in normal skin. By electron microscopy we observed that the melanocytes in the lesional skin were round and less dendritic with fewer melanosomes than in normal pigment cells. Lesions gently frozen with liquid nitrogen repigmented in 6 to 8 weeks. The number of dopa-positive melanocytes was significantly greater in the repigmented areas than in untreated lesions but less than in normal skin.

Biology of hypopigmentation

A review of the basics of pigment cell biology is followed by a discussion of the characteristics of several disorders of hypopigmentation. By determining such features as inheritance pattern, time of onset (congenital, childhood, adulthood), natural history (stable vs progressive), type of pigment loss (diffuse or circumscribed), distribution of lesions (generalized vs localized), degree of pigment loss (incomplete or complete), number of melanocytes, if any, in biopsy specimens of affected areas, type of melanocytic dysfunction, and associated inflammation or infection, one can classify the disorders of hypopigmentation. The proposed pathophysiology for each disorder of hypomelanosis is presented.

Leukoderma punctata

Thirteen patients with vitiligo (1 segmental, 4 focal, 8 generalized) aged 7 to 38, most of them female children, developed numerous punctate hypopigmented and achromic spots. The spots measured 0.5 to 1.5 mm and were located primarily on the sun-exposed areas of the extremities; they appeared following treatment with PUVASOL. Two of these patients experienced a reduction of this leukodermic defect, whereas the remaining patients showed a stable clinical course. Dopa and Fontana stains disclosed, in most cases, decreased but not absent functional melanocytes and a marked reduction of melanin. Ultrastructural studies demonstrated slight to severe damage of keratinocytes and melanocytes similar to that previously reported in vitiligo patients. The phototoxic effect of PUVASOL therapy is suggested as a possible etiologic factor in these patients. A probable relationship among idiopathic guttate hypomelanosis, leukoderma punctata, and vitiligo is discussed.