|Year : 2017 | Volume
| Issue : 1 | Page : 13-20
Hypopigmentary disorders in Asian patients
Prasad Kumarasinghe MD, Clinical Associate Professor 1, Shraddha Uprety2, Rashmi Sarkar3
1 Department of Dermatology, Fiona Stanley Hospital, Murdoch, Western Australia, Australia
2 Deparment of Dermatology, Chitwan Medical College and Teaching Hospital, Bharatpur, Chitwan, Nepal
3 Department of Dermatology, MAMC and Associated LNJP Hospital, New Delhi, Delhi, India
|Date of Web Publication||19-Jun-2017|
Department of Dermatology, Fiona Stanley Hospital, Murdoch, Western Australia
Source of Support: None, Conflict of Interest: None
Asia is geographically, racially and culturally diverse. This leads to variations in the skin types and pigmentary disorders affecting the Asian skin. This review briefly outlines the various hypopigmentary disorders affecting the Asian skin. Several of these disorders are idiopathic in origin, whereas some are due to autoimmune mechanisms, infections or secondary to inflammation of the skin. Hypopigmentary disorders often have a significant psychological impact. The treatment of these disorders is diverse and depends on the cause of hypopigmentation.
Keywords: Asian patients, clear cell papulosis, hypopigmentary disorders, leprosy, pityriasis alba, pityriasis versicolor, post kala-azar dermal leishmaniasis, vitiligo
|How to cite this article:|
Kumarasinghe P, Uprety S, Sarkar R. Hypopigmentary disorders in Asian patients. Pigment Int 2017;4:13-20
| Introduction|| |
Asia is a diverse continent with billions of people with pigmented skin. The legacy of having a pigmented skin is that while one is relatively better protected against sun-related skin damage and skin cancer, however, even the subtle changes of pigmentation are obvious in the dark-skinned individuals.,,
In the recent past, partly due to increasing affluence of many Asian communities, disorders of pigmentation have received a lot of attention. The translation of this interest into basic science research has not occurred yet in many Asian countries. It would be prudent for the dermatologists and researchers across Asia to engage more in research concerning the disorders of pigmentation, their molecular, cellular and genetic bases as well as various treatment modalities.
There are many pigmentary disorders that are unique or more predominant among the Asians. The two major determinants for this difference are the genetic factors and the climatic factors. Cultural practices also dictate the manifestation of certain pigmentary disorders (e.g. the side effects of the use of strong bleaching agents such as hydroquinone). In addition, there are some unclassified disorders of pigmentation that need to be characterized and classified. Correct terminology of pigmentary disorders is important to avoid confusions in literature searches.,,,,
Mongoloid, Caucasoid and many mixed populations are seen among the Asian ethnic groups. Increasing global migration and inter-racial marriages have taken many typically Asian pigmentary disorders to other parts of the world.
In some Asian countries, marriages between blood relatives such as cousins are common. In such communities, genetically determined rare disorders are more commonly seen.
Some lesions are purely macular (e.g. vitiligo), whereas some have textural changes (e.g. leprosy). Post-inflammatory hypopigmentation and depigmentation secondary to burns too are significant problems in patients with dark skin.
This article presents an overview of the hypopigmentary disorders that are seen among Asians.
The details of each condition are not described here, as it would be a rather lengthy discourse. The hypopigmented skin lesions can occur due to congenital, autoimmune, infective, mechanical or inflammatory causes, or they can be idiopathic. The common hypopigmentary disorders in Asian countries are summarized in [Table 1], [Figure 1], [Figure 2], [Figure 3], [Figure 4] and [Figure 5], and a list of the hypopigmentary disorders seen in the patients in the Indian subcontinent is given in [Table 2], [Figure 6], [Figure 7],[Figure 8], [Figure 9] and [Figure 10]. [Table 3] illustrates some conditions that appear to be more common among those belonging to the Oriental races. Some depigmented/hypopigmented disorders that are rare now as compared to the past include pinta (caused by Treponema carateum) and pintoid dyschromia of yaws (caused by Treponema pertenue).
|Table 1: Common hypopigmentary/depigmentary disorders among the population in Asian countries [Figure1-5]|
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|Table 2: Hypopigmentary conditions in populations living in the Indian subcontinent [Figure 6-10]|
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|Table 3: Hypopigmentary conditions more common among the Oriental populations|
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|Figure 5: Vitiligo − incidentally this patient had lepromatous leprosy as well|
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|Figure 8: Tuberculoid leprosy with a typical hypopigmented lesion (the scar is unrelated)|
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|Figure 10: Hypopigmentation due to prolonged used of strong topical corticosteroid|
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We shall now proceed to discuss briefly about some common hypopigmentary disorders affecting the Asian population.
| Leprosy|| |
Leprosy is characterized by hypopigmented-to-erythematous patches and plaques with variable sensory loss. India alone accounts for 58.85% of the global burden of leprosy. Macular hypopigmented lesions are seen throughout the spectrum of leprosy from indeterminate leprosy to lepromatous leprosy. They are mainly localized on the face, the knees and the elbows, the buttocks and the ears. Various theories have been put forward to explain the hypopigmentation seen in leprosy. The melanocytes show decreased activity, and defective transfer of melanin from the melanocytes to the keratinocytes have been observed., The melanocytes have been seen to have vacuolization, a dilated endoplasmic reticulum and a decreased number of mitochondria. These changes in the melanocytes have been attributed to the ischemic changes and consumption of dopamine substrate by Mycobacterium leprae. Leprosy lesions usually spare the palms and the soles, the midline of the back and the hairy areas of the body such as the scalp, the axillae and the genitals. Typical leprosy lesions are ill- to well-defined, dry lesions with sparse hair and decreased sweating. The lesions are usually hypoaesthetic. The peripheral nerves are often enlarged. In the Indian subcontinent, a sensory examination of a hypopigmented patch is mandatory. However, one must remember that leprosy is a great mimic and could have variable manifestations. Discussing all the variables manifested by leprosy is beyond the scope of this review. The patient must always be examined in natural light after adequate exposure. The differentials include pityriasis alba (PA), pityriasis versicolor (PV), post-kala-azar dermal leishmaniasis (PKDL) and hypopigmented mycosis fungoides (HMF).
Slit skin smear (SSS) should be performed whenever possible. The histopathology in leprosy is variable ranging from granulomas packed with epitheloid cells seen in tuberculoid pole to heavily parasitized macrophages with prominent grenz zone seen in the lepromatous pole. Perineural infiltration by the inflammatory cells is seen in the indeterminate form. Fite staining of the histopathology specimen of leprosy should always be performed to investigate for bacilli.
| Post-Kala-Azar Dermal Leishmaniasis (PKDL)|| |
PKDL is a condition seen in the kala-azar endemic areas of the Indian subcontinent and Sudan. PKDL follows visceral leishmaniasis or kala-azar, though overt history may be absent in some patients. This is due to subclinical infection in some patients. Visceral leishmaniasis precedes the Indian PKDL by a few months to several years, whereas in the Sudanese form, visceral leishmaniasis occurs concomitantly or just a few months before PKDL. After successful treatment of visceral leishmaniasis, 10–20% of the patients in India and 50–60% of the patients in Sudan develop PKDL. The most common agent causing PKDL is Leishmania donovani.
The clinical presentation of PKDL is often polymorphic with combination of erythematous plaques, papulonodular lesions or hypopigmented patches. At any point of time, a particular morphologic type may be more predominant. Hypopigmented presentation is considered rare and accounts for 10% of the presentation. Occasionally, the depigmentation is so severe that it may mimic vitiligo. PKDL is more common in young adults in India, and among those aged 4–8 years in Sudan. The lesions usually begin on the face and then spread to other areas of the body. The lesions do not have the tendency to coalesce with one another. They spare the central back, the belt areas and the friction sites until late in the disease course. Mucosal involvement is rare. The cause of hypopigmentation in PDKL is not well understood. It has been hypothesized that the granuloma formed in lesions of PKDL interferes with the pigment metabolism and leads to hypopigmentation. Decrease in the melanocytes as well as abnormalities in the melanosomes have been observed in PKDL. These maybe secondary to the oxidative injury to the melanosomes by the macrophages, which produce superoxide radicals to kill the parasites. L. donovani secretes proteases that decrease the extracellular matrix components of the host tissue and, thereby, decrease the melanocyte attachment. Leprosy is another common differential. Leucoderma syphiliticum is a rare condition that should be kept in mind. The clinical differences between leprosy, PKDL and vitiligo are elaborated in [Table 4].
Histopathology of the lesional skin shows mild perivascular infiltration by lymphocytes and histiocytes with or without plasma cells. L. donovani bodies are rare. Occasionally, histopathology is non-specific at the macular stage. Culture is considered as the gold standard for demonstrating the presence of Leishmania; however, it is time consuming, and the results are often negative. Polymerase chain reaction and nucleic acid sequence based amplification tests are sensitive and specific. An enzyme-linked immunosorbent assay using RK-39, Leishmania-sensitive recombinant antigen can be used for detection on serum samples and has a sensitivity of 95–100% and a specificity of 90–95%., Often, it is the clinical presentation with corroborative history of kala-azar that clinches the diagnosis.
| Vitiligo|| |
Vitiligo is a chronic autoimmune depigmenting disorder affecting the skin, the mucosa and the hair. It is a complex disorder that merits a discourse of its own and is beyond the scope of this review. The clinical differences between vitiligo, PKDL and leprosy are elaborated in [Table 4]. Vitiligo can affect the quality of life and causes severe psychological effects in dark-skinned patients, with associated social stigma in some communities.
Hypopigmented mycosis fungoides
HMF is an interesting variant of mycosis fungoides (MF) with almost exclusive presentation in the dark-skinned Asian population. HMF accounts for 17–59% of all the MF cases seen in the pediatric age group. It is characterized as hypopigmented-to-depigmented lesions. The lesions are usually present on the trunk and on the proximal limbs; however, variations to this might be present. The lesions are variable in size and number. Occasionally, a single lesion might be present as well. The lesions can be pruritic in nature. The surface of the lesion might show telangiectasia or atrophy and may become more prominent on sun exposure. Mixed mycosis fungoides have been described as having pleomorphic morphologic lesions and having few hypopigmented-to-depigmented lesions as well. However, primary HMF is a distinct clinical variant of MF with some peculiarities of its own.
Histopathology is characterized by lymphocytic infiltrate in the dermis. Focal parakeratosis and variable spongiosis may be observed. Intense epidermotropism has been observed in several cases, characterized by large, haloed and atypical lymphocytes with convoluted nuclei. Pautrier’s microabscesses are rarely described. Immunohistochemistry is peculiar, as the epidermotropic lymphocytes in HMF are CD8+ unlike CD4+ in other variants of MF. The CD8+ cells are hypothesized to exert cytotoxic effects on the melanocytes leading to hypopigmentation.,
HMF generally has good prognosis and does not progress beyond stage I B (defined by the International Society of Cutaneous Lymphomas as lesions covering >10% of the body surface area without involvement of the lymph nodes or the viscera)., However, deaths have been reported. Hence, in spite of good prognosis, HMF should always be treated as a malignant disease and patient should be monitored regularly. However, highly aggressive treatment is not advised in these patients. This is due to good prognosis of the disease and high recurrence rate after treatment.
PV is characterized usually by hypopigmented and occasionally by hyperpigmented macules, which may initially be perifollicular in distribution but later coalesce to produce patches with irregular borders. They have characteristic fine scales and are mainly localized to the seborrhoeic areas of the body such as the chest, the neck, the upper back and the face. The scales become more prominent on rubbing or scraping the lesions. The lesions also show mild wrinkling. Pruritus is uncommon. The age group commonly affected is between 10 and 30 years, and recurrence is seen yearly in most cases. In temperate climates, up to 40% of the population may be affected. The annual incidence rate is 5.2–8.3%. PV is commonly caused by fungi of Malassezia sp. The most common aetiological agent of PV varies with geography and age. In some studies, Malassezia globosa is seen as the most common aetiologic agent, and in some others, Malassezia sympodialis. The species composition varies with age related changes in the sebaceous gland and sebum composition. Hypopigmentation is attributed to the competitive inhibition of tyrosinase by the azelaic acid produced by Malassezia. Additionally, Malassezia also causes apoptosis of the melanocytes. A simple, bedside diagnostic technique for PV is KOH mount of the scales. A 10% KOH mount shows non-septate, short hyphae and a bunch of spores in ‘spaghetti and meatball’ appearance. In Wood’s lamp examination, PV gives a yellow fluorescence. Biopsy is not required.
PA is a pigmentary disorder mainly affecting children. It has a prevalence of 1.9–5.2% and is more often seen among the people belonging to the darkly pigmented races. PA presents as hypo-to-depigmented macule, usually located on the perioral distribution, the lips, the cheek and the chin. These macules have slight scaling on the border. PA may be associated with atopic dermatitis or may be idiopathic in origin. Hence, it is imperative to examine for other cutaneous signs of atopic dermatitis such as xerosis, Dennie–Morgan lines, palmar hyperlinearity and atopic dirty neck. Atopy-related family and personal history too should be checked. PA responds to emollients, mild topical corticosteroids and topical tacrolimus or pimecrolimus. The differentials include PV, vitiligo, indeterminate leprosy, post-inflammatory hypopigmentation and hypopigmented polymorphic light eruption.
Idiopathic guttate hypomelanosis
Idiopathic guttate hypomelanosis (IGH) is characterized by well-defined oval-to-round depigmented porcelain white macules of sizes ranging from 0.5 to 6 mm, some of them being as large as 2.5 cm. They are observed more frequently on the sun-exposed areas of the body. The common sites include the arms and the shins, but sometimes are widespread. In three-quarters of the patients, they involve the sites not exposed to the sun. IGH is uncommon on the face, where it occasionally involves the margins. They are usually few, but may be numerous. The number of IGH lesions increases with age from 41% in the age group of 31–40 years to 97% in the age group of 81–90 years. The hair is not involved in IGH. They are often a result of the chronic UV-induced damage of the skin. Histopathologically, they show decrease in the melanocytes and melanin content compared to the adjoining skin. Differentials include vitiligo, progressive macular hypomelanosis, PV and lichen sclerosus atrophicans.
Clear cell papulosis
Clear cell papulosis is a rare condition seen predominantly in the infants and young children, particularly those belonging to the Oriental races (mostly reported among the Chinese and Koreans). Small asymptomatic macules or slightly elevated flat papules appear on the pubic region and the abdomen. They may appear along the milk line. Histopathology shows clear cells in the basal and supra-basal layers of the epidermis on haematoxylin and eosin staining. These are often positive for mucin stains and CK7 and CEA. The significance of these lesions is not known. No specific treatment is required.,
| Impact of Cultural Practices And Impact of Disease on The Patients|| |
The impact of pigmentary disorders such as vitiligo among the dark-skinned populations, particularly in India, can be enormous. Sometimes such diseases can greatly affect the quality of life and can even cause depression and suicide. Therefore, dermatologists and primary care physicians should address the associated psychological and psychiatric issues and take appropriate measures for the holistic care of the patients.
Some fairer-skinned Asians (e.g. north Indian, Iranian, Iraqi, etc.) have pigmentary problems similar to some Western populations. However, one difference is that Asians with fairer skin generally avoid excessive sun exposure as opposed to fair-skinned people living in Western countries, mainly because of their socio-cultural practices. These cultural practices mean that even among the fairer-skinned Asians, sun-related dyspigmentation is less common or less extensive, for example, IGH in sun-exposed areas.
Albinos living in tropical Asian countries often are not resourceful or not educated sufficiently to use appropriate sun protection measures. Therefore, such patients can have solar keratoses as well as skin malignancies.
Chronic contact dermatitis due to application of ‘bindi’ on the forehead may cause a peculiar depigmented spot on the forehead among some Indian patients.
Regular drinking of arsenic-contaminated well water (ground water) can lead to chronic arsenic poisoning with associated raindrop depigmentation.
Prolonged unsupervised use of strong topical steroids can also cause hypopigmentation of the skin in the areas of application, in addition to skin atrophy.
| Treatment of Hypopigmentation|| |
The treatment of diverse hypopigmentary disorders/lesions depends on the type of disease. For example, post-inflammatory hypopigmentation improves with time, and hypopigmentation of PV fades slowly after the treatment of the condition. Conditions such as vitiligo may benefit from medical, physical (UV light) as well as surgical options of treatment. The psychological impact of depigmented or hypopigmented lesions on the patients’ perception of their body image too needs to be addressed. Hypopigmented lesions secondary to infective diseases such as leprosy may not repigment fully even after successful treatment of the infection.
Camouflage also becomes an important management option in hypopigmentary conditions, as patients are extremely worried about the visibility of the differential pigmentation. The quality of life and the mental stress of such patients can be greatly reduced by using camouflage creams. Counselling and psychiatric referrals may be appropriate in some cases.
Post-inflammatory hypopigmentation is a major concern in the dark-skinned patients with regard to deep chemical peels, deep cryotherapy, laser resurfacing, IPL treatment and electrocautery. The clinicians should weigh the pros and cons of such treatments and discuss the potential side effects of such treatments before starting of these procedures.
Although chronic arsenic poisoning is classically described in Bangladesh, it can also occur in other countries such as India and China. Providing safe drinking water to these communities is important to prevent most of the serious effects of chronic arsenic poisoning.
| Conclusion|| |
Hypopigmentary disorders are a diverse group of pigmentary disorders. There are several common and uncommon hypopigmentary disorders in Asia. It is important to identify the causes and treat them appropriately whenever possible. It is important to understand the psychological stress of the patients caused by their pigmentary disorder. More focussed research should be performed on these fascinating disorders of pigmentation.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10]
[Table 1], [Table 2], [Table 3], [Table 4]